Abstract:

Methods, apparatus and systems for performing a marking operation to mark
a presence or absence of at least one underground facility using a
marking device. Marking material is dispensed onto a target surface via
actuation of an actuation system of the marking device. A location
tracking system detects a location of the marking device. One or more
input devices of the marking device detect(s) one or more operating
conditions of the marking device, and marking information is logged into
local memory of the marking device. In one aspect, at least some
operating information relating to the one or more detected conditions of
the marking device are included in the marking information logged into
memory.

Claims:

1. A marking apparatus for performing a marking operation to indicate a
presence or an absence of at least one underground facility, the marking
apparatus comprising:a hand-held housing;a holder configured to hold to
the hand-held housing at least one marking dispenser containing a marking
material;a location tracking system mechanically coupled to the hand-held
housing and configured to determine a location of the apparatus;at least
one processor communicatively coupled to the location tracking system;
andat least one input device communicatively coupled to the at least one
processor, configured to sense at least one operating condition of the
apparatus, and provide an output signal to the at least one processor
indicative of the sensed at least one operating condition.

2. The apparatus of claim 1, wherein the at least one input device
comprises an inclinometer and wherein the at least one operating
condition is a degree of inclination of the apparatus.

3. The apparatus of claim 1, further comprising a marking material
detection mechanism communicatively coupled to the at least one processor
to provide an output signal to the at least one processor.

4. The apparatus of claim 1, wherein the at least one input device
comprises a compass and wherein the at least one operating condition is a
heading of the apparatus.

5. The apparatus of claim 1, wherein the at least one input device is a
temperature sensor and wherein the at least one operating condition is a
temperature of the at least one processor.

6. The apparatus of claim 1, wherein the at least one input device is a
temperature sensor and wherein the at least one operating condition is a
temperature internal to the hand-held housing.

7. The apparatus of claim 1, wherein the at least one input device is a
proximity sensor and the at least one operating condition is a distance
between the apparatus and a target surface.

8. The apparatus of claim 7, wherein the distance between the apparatus
and a target surface is a distance between the location tracking system
and physical ground.

9. The apparatus of claim 7, wherein the distance between the apparatus
and a target surface is a distance between a tip of the apparatus and a
surface on which marking material is to be dispensed.

10. The apparatus of claim 1, wherein the at least one input device is a
yaw rate sensor and wherein the at least one operating condition is a yaw
rate of the apparatus.

11. The apparatus of claim 1, wherein the at least one input device is an
accelerometer and wherein the at least one operating condition is an
acceleration of the apparatus.

12. The apparatus of claim 11, wherein the accelerometer is a three-axis
accelerometer and wherein the at least one operating condition is a
respective acceleration for each of the three axes.

13. The apparatus of claim 11, wherein the accelerometer is a three-axis
accelerometer and wherein the at least one operating condition is a
combined acceleration for all three axes.

14. The apparatus of claim 11, wherein the accelerometer is a first
accelerometer, and wherein the at least one input device comprises a
second accelerometer configured to measure an acceleration of the
apparatus.

15. The apparatus of claim 14, wherein the first accelerometer is disposed
at a first position of the hand-held housing and the second accelerometer
is disposed at a second position of the hand-held housing.

16. The apparatus of claim 15, wherein the first accelerometer is disposed
proximate a tip of the apparatus and the second accelerometer is disposed
proximate the location tracking system.

17. The apparatus of claim 15, wherein the first accelerometer is disposed
proximate a tip of the apparatus and the second accelerometer is disposed
proximate a top of the apparatus.

18. The apparatus of claim 1, wherein the at least one input device
comprises a pressure sensor and wherein the at least one operating
condition is a pressure applied to at least a portion of the hand-held
housing.

19. The apparatus of claim 18, wherein the hand-held housing includes a
handle, and wherein the at least one operating condition is a pressure
applied to the handle.

20. The apparatus of claim 18, wherein the hand-held housing includes a
trigger, and wherein the at least one operating condition is a pressure
applied to the trigger.

21. The apparatus of claim 20, wherein the trigger forms at least part of
an actuation mechanism configured to control dispensing of the marking
material.

22. The apparatus of claim 1, wherein the at least one input device is a
device health sensor and wherein the at least one operating condition is
indicative of an operating state of at least one component of the
apparatus.

23. The apparatus of claim 1, wherein the at least one input device
comprises an audio recorder and wherein the at least one operating
condition is an acoustic signal emitted by the at least one marking
dispenser.

24. The apparatus of claim 23, further comprising a microphone coupled to
the audio recorder and configured to detect the acoustic signal and
provide an analog representation of the acoustic signal to the audio
recorder.

25. The apparatus of claim 1, wherein the at least one input device
comprises an image capture device.

26. The apparatus of claim 25, wherein the at least one operating
condition is a condition of the marking material dispensed by the
apparatus, and wherein the output signal forms at least part of an image
of dispensed marking material.

27. The apparatus of claim 26, wherein the image capture device is further
configured to provide to the at least one processor at least one output
signal indicative of an operating state of the image capture device.

28. The apparatus of claim 25, wherein the at least one operating
condition is an operating state of the image capture device.

29. The apparatus of claim 28, wherein the operating state of the image
capture device is a mode of operation of the image capture device.

30. The apparatus of claim 1, wherein the at least one processor is
mechanically coupled to the at least one housing.

31. The apparatus of claim 1, wherein the at least one processor is
disposed within the hand-held housing.

32. A method for performing a marking operation to mark a presence or
absence of at least one underground facility using a marking device, the
method comprising:A) dispensing, via actuation of an actuation system of
the marking device, marking material onto a target surface;B) detecting,
via a location tracking system, a location of the marking device;C)
detecting, via at least one input device of the marking device, at least
one operating condition of the marking device; andD) logging into local
memory of the marking device marking information relating at least in
part to A), B), and C).

33. The method of claim 32, wherein C) comprises detecting a degree of
inclination of the marking device.

34. The method of claim 32, further comprising E) detecting, via a marking
material detection mechanism of the marking device, at least one
characteristic of the marking material.

35. The method of claim 32, wherein C) comprises detecting a heading of
the marking device.

36. The method of claim 32, wherein C) comprises detecting a temperature
of a processor of the marking device.

37. The method of claim 32, wherein the marking device includes a
hand-held housing in which the local memory is disposed, and wherein C)
comprises detecting a temperature internal to the hand-held housing.

38. The method of claim 32, wherein C) comprises detecting a distance
between the marking device and a target surface.

39. The method of claim 38, wherein detecting a distance between the
marking device and a target surface comprises detecting a distance
between the location tracking system and physical ground.

40. The method of claim 38, wherein detecting a distance between the
marking device and a target surface comprises detecting a distance
between a tip of the marking device and a surface on which marking
material is to be dispensed.

42. The method of claim 32, wherein C) comprises detecting an acceleration
of the marking device.

43. The method of claim 42, wherein detecting an acceleration of the
marking device comprises detecting a respective acceleration along each
of three axes of the marking device.

44. The method of claim 42, wherein detecting an acceleration of the
marking device comprises detecting a combined acceleration along three
axes of the marking device.

45. The method of claim 42, wherein detecting an acceleration of the
marking device comprises detecting an acceleration of a first point of
the marking device and detecting an acceleration of a second point of the
marking device.

46. The method of claim 45, wherein the first point of the marking device
corresponds to a tip of the marking device and wherein the second point
of the marking device corresponds to a position of the location tracking
system.

47. The method of claim 45, wherein the first point of the marking device
corresponds to a tip of the marking device and wherein the second point
of the marking device corresponds to a top of the marking device.

48. The method of claim 32, wherein the marking device includes a
hand-held housing and wherein C) comprises detecting a pressure applied
to at least a portion of the hand-held housing.

49. The method of claim 48, wherein the hand-held housing includes a
handle, and wherein detecting a pressure applied to at least a portion of
the hand-held housing comprises detecting a pressure applied to the
handle.

50. The method of claim 48, wherein the hand-held housing includes a
trigger, and wherein detecting a pressure applied to at least a portion
of the hand-held housing comprises detecting a pressure applied to the
trigger.

51. The method of claim 32, wherein C) comprises detecting a condition
indicative of whether a component of the marking device is operating
correctly.

52. The method of claim 32, wherein C) comprises detecting an acoustic
signal generated by dispensing of the marking material in A).

54. At least one computer readable storage medium storing
processor-executable instructions which, when executed by at least one
processor, perform a method for facilitating a marking operation to mark
a presence or absence of at least one underground facility using a
marking device, the method comprising:A) detecting, via a location
tracking system, a location of the marking device;B) detecting, via at
least one input device of the marking device, at least one operating
condition of the marking device; andC) logging into local memory of the
marking device marking information relating at least in part to A) and
B).

[0004]Ser. No. 12/703,958 also claims a priority benefit, under 35 U.S.C.
§119(e), to U.S. Provisional Application Ser. No. 61/232,112,
entitled "Methods and Apparatus for Detecting and Monitoring Use of
Locating Equipment for Out-Of-Tolerance Conditions," filed on Aug. 7,
2009 under attorney docket number D0687.70042US00.

[0005]Ser. No. 12/703,958 also claims a priority benefit, under 35 U.S.C.
§120, as a continuation-in-part (CIP) of U.S. Non-provisional
application Ser. No. 12/568,087, entitled "Methods and Apparatus for
Generating an Electronic Record of Environmental Landmarks based on
Marking Device Actuations," filed on Sep. 28, 2009 under attorney docket
number D0687.70014US01.

[0007]Ser. No. 12/568,087 also claims a priority benefit, under 35 U.S.C.
§120, as a continuation-in-part (CIP) of U.S. Non-provisional
application Ser. No. 12/539,497, entitled "Methods and Apparatus for
Generating an Electronic Record of a Marking Operation based on Marking
Device Actuations," filed on Aug. 11, 2009 under attorney docket number
D0687.70011US01.

[0008]Ser. No. 12/539,497 in turn claims the benefit, under 35 U.S.C.
§119(e), of U.S. Provisional Application Ser. No. 61/102,151,
entitled "Data acquisition system for and method of analyzing marking
operations based on marking device actuations," filed on Oct. 2, 2008
under attorney docket number D0687.70011US00.

[0009]Each of the above-identified applications is incorporated by
reference herein in its entirety.

[0011]Field service operations may be any operation in which companies
dispatch technicians and/or other staff to perform certain activities,
for example, installations, services and/or repairs. Field service
operations may exist in various industries, examples of which include,
but are not limited to, network installations, utility installations,
security systems, construction, medical equipment, heating, ventilating
and air conditioning (HVAC) and the like.

[0012]An example of a field service operation in the construction industry
is a so-called "locate and marking operation," also commonly referred to
more simply as a "locate operation" (or sometimes merely as "a locate").
In a typical locate operation, a locate technician visits a work site in
which there is a plan to disturb the ground (e.g., excavate, dig one or
more holes and/or trenches, bore, etc.) so as to determine a presence or
an absence of one or more underground facilities (such as various types
of utility cables and pipes) in a dig area to be excavated or disturbed
at the work site. In some instances, a locate operation may be requested
for a "design" project, in which there may be no immediate plan to
excavate or otherwise disturb the ground, but nonetheless information
about a presence or absence of one or more underground facilities at a
work site may be valuable to inform a planning, permitting and/or
engineering design phase of a future construction project.

[0013]In many states, an excavator who plans to disturb ground at a work
site is required by law to notify any potentially affected underground
facility owners prior to undertaking an excavation activity. Advanced
notice of excavation activities may be provided by an excavator (or
another party) by contacting a "one-call center." One-call centers
typically are operated by a consortium of underground facility owners for
the purposes of receiving excavation notices and in turn notifying
facility owners and/or their agents of a plan to excavate. As part of an
advanced notification, excavators typically provide to the one-call
center various information relating to the planned activity, including a
location (e.g., address) of the work site and a description of the dig
area to be excavated or otherwise disturbed at the work site.

[0014]A locate operation typically is initiated as a result of an
excavator providing an excavation notice to a one-call center. An
excavation notice also is commonly referred to as a "locate request," and
may be provided by the excavator to the one-call center via an electronic
mail message, information entry via a website maintained by the one-call
center, or a telephone conversation between the excavator and a human
operator at the one-call center. The locate request may include an
address or some other location-related information describing the
geographic location of a work site at which the excavation is to be
performed, as well as a description of the dig area (e.g., a text
description), such as its location relative to certain landmarks and/or
its approximate dimensions, within which there is a plan to disturb the
ground at the work site. One-call centers similarly may receive locate
requests for design projects (for which, as discussed above, there may be
no immediate plan to excavate or otherwise disturb the ground).

[0015]Once facilities implicated by the locate request are identified by a
one-call center, the one-call center generates a "locate request ticket"
(also known as a "locate ticket," or simply a "ticket"). The locate
request ticket essentially constitutes an instruction to inspect a work
site and typically identifies the work site of the proposed excavation or
design and a description of the dig area, typically lists on the ticket
all of the underground facilities that may be present at the work site
(e.g., by providing a member code for the facility owner of an
underground facility), and may also include various other information
relevant to the proposed excavation or design (e.g., the name of the
excavation company, a name of a property owner or party contracting the
excavation company to perform the excavation, etc.). The one-call center
sends the ticket to one or more underground facility owners and/or one or
more locate service providers (who may be acting as contracted agents of
the facility owners) so that they can conduct a locate and marking
operation to verify a presence or absence of the underground facilities
in the dig area. For example, in some instances, a given underground
facility owner may operate its own fleet of locate technicians, in which
case the one-call center may send the ticket to the underground facility
owner. In other instances, a given facility owner may contract with a
locate service provider to receive locate request tickets and perform a
locate and marking operation in response to received tickets on their
behalf.

[0016]Upon receiving the locate request, a locate service provider or a
facility owner (hereafter referred to as a "ticket recipient") may
dispatch a locate technician to the work site of planned excavation to
determine a presence or absence of one or more underground facilities in
the dig area to be excavated or otherwise disturbed. A typical first step
for the locate technician includes utilizing an underground facility
"locate device," which is an instrument or set of instruments (also
referred to commonly as a "locate set") for detecting facilities that are
concealed in some manner, such as cables and pipes that are located
underground. The locate device is employed by the technician to verify
the presence or absence of underground facilities indicated in the locate
request ticket as potentially present in the dig area (e.g., via the
facility owner member codes listed in the ticket). This process is often
referred to as a "locate operation."

[0017]In one example of a locate operation, an underground facility locate
device is used to detect electromagnetic fields that are generated by an
applied signal provided along a length of a target facility to be
identified. In this example, a locate device may include both a signal
transmitter to provide the applied signal (e.g., which is coupled by the
locate technician to a tracer wire disposed along a length of a
facility), and a signal receiver which is generally a hand-held apparatus
carried by the locate technician as the technician walks around the dig
area to search for underground facilities. The transmitter is connected
via a connection point to a target object (in this example, underground
facility) located in the ground, and generates the applied signal coupled
to the underground facility via the connection point (e.g., to a tracer
wire along the facility), resulting in the generation of a magnetic
field. The magnetic field in turn is detected by the locate receiver,
which itself may include one or more detection antenna. The locate
receiver indicates a presence of a facility when it detects
electromagnetic fields arising from the applied signal. Conversely, the
absence of a signal detected by the locate receiver generally indicates
the absence of the target facility.

[0018]In yet another example, a locate device employed for a locate
operation may include a single instrument, similar in some respects to a
conventional metal detector. In particular, such an instrument may
include an oscillator to generate an alternating current that passes
through a coil, which in turn produces a first magnetic field. If a piece
of electrically conductive metal is in close proximity to the coil (e.g.,
if an underground facility having a metal component is below/near the
coil of the instrument), eddy currents are induced in the metal and the
metal produces its own magnetic field, which in turn affects the first
magnetic field. The instrument may include a second coil to measure
changes to the first magnetic field, thereby facilitating detection of
metallic objects.

[0019]In addition to the locate operation, the locate technician also
generally performs a "marking operation," in which the technician marks
the presence (and in some cases the absence) of a given underground
facility in the dig area based on the various signals detected (or not
detected) during the locate operation. For this purpose, the locate
technician conventionally utilizes a "marking device" to dispense a
marking material on, for example, the ground, pavement, or other surface
along a detected underground facility. Marking material may be any
material, substance, compound, and/or element, used or which may be used
separately or in combination to mark, signify, and/or indicate. Examples
of marking materials may include, but are not limited to, paint, chalk,
dye, and/or iron. Marking devices, such as paint marking wands and/or
paint marking wheels, provide a convenient method of dispensing marking
materials onto surfaces, such as onto the surface of the ground or
pavement.

[0020]FIGS. 1A and 1B illustrate a conventional marking device 50 with a
mechanical actuation system to dispense paint as a marker. Generally
speaking, the marking device 50 includes a handle 38 at a proximal end of
an elongated shaft 36 and resembles a sort of "walking stick," such that
a technician may operate the marking device while standing/walking in an
upright or substantially upright position. A marking dispenser holder 40
is coupled to a distal end of the shaft 36 so as to contain and support a
marking dispenser 56, e.g., an aerosol paint can having a spray nozzle
54. Typically, a marking dispenser in the form of an aerosol paint can is
placed into the holder 40 upside down, such that the spray nozzle 54 is
proximate to the distal end of the shaft (close to the ground, pavement
or other surface on which markers are to be dispensed).

[0021]In FIGS. 1A and 1B, the mechanical actuation system of the marking
device 50 includes an actuator or mechanical trigger 42 proximate to the
handle 38 that is actuated/triggered by the technician (e.g., via
pulling, depressing or squeezing with fingers/hand). The actuator 42 is
connected to a mechanical coupler 52 (e.g., a rod) disposed inside and
along a length of the elongated shaft 36. The coupler 52 is in turn
connected to an actuation mechanism 58, at the distal end of the shaft
36, which mechanism extends outward from the shaft in the direction of
the spray nozzle 54. Thus, the actuator 42, the mechanical coupler 52,
and the actuation mechanism 58 constitute the mechanical actuation system
of the marking device 50.

[0022]FIG. 1A shows the mechanical actuation system of the conventional
marking device 50 in the non-actuated state, wherein the actuator 42 is
"at rest" (not being pulled) and, as a result, the actuation mechanism 58
is not in contact with the spray nozzle 54. FIG. 1B shows the marking
device 50 in the actuated state, wherein the actuator 42 is being
actuated (pulled, depressed, squeezed) by the technician. When actuated,
the actuator 42 displaces the mechanical coupler 52 and the actuation
mechanism 58 such that the actuation mechanism contacts and applies
pressure to the spray nozzle 54, thus causing the spray nozzle to deflect
slightly and dispense paint. The mechanical actuation system is
spring-loaded so that it automatically returns to the non-actuated state
(FIG. 1A) when the actuator 42 is released.

[0023]In some environments, arrows, flags, darts, or other types of
physical marks may be used to mark the presence or absence of an
underground facility in a dig area, in addition to or as an alternative
to a material applied to the ground (such as paint, chalk, dye, tape)
along the path of a detected utility. The marks resulting from any of a
wide variety of materials and/or objects used to indicate a presence or
absence of underground facilities generally are referred to as "locate
marks." Often, different color materials and/or physical objects may be
used for locate marks, wherein different colors correspond to different
utility types. For example, the American Public Works Association (APWA)
has established a standardized color-coding system for utility
identification for use by public agencies, utilities, contractors and
various groups involved in ground excavation (e.g., red=electric power
lines and cables; blue=portable water; orange=telecommunication lines;
yellow=gas, oil, steam). In some cases, the technician also may provide
one or more marks to indicate that no facility was found in the dig area
(sometimes referred to as a "clear").

[0024]As mentioned above, the foregoing activity of identifying and
marking a presence or absence of one or more underground facilities
generally is referred to for completeness as a "locate and marking
operation." However, in light of common parlance adopted in the
construction industry, and/or for the sake of brevity, one or both of the
respective locate and marking functions may be referred to in some
instances simply as a "locate operation" or a "locate" (i.e., without
making any specific reference to the marking function). Accordingly, it
should be appreciated that any reference in the relevant arts to the task
of a locate technician simply as a "locate operation" or a "locate" does
not necessarily exclude the marking portion of the overall process. At
the same time, in some contexts a locate operation is identified
separately from a marking operation, wherein the former relates more
specifically to detection-related activities and the latter relates more
specifically to marking-related activities.

[0025]Inaccurate locating and/or marking of underground facilities can
result in physical damage to the facilities, property damage, and/or
personal injury during the excavation process that, in turn, can expose a
facility owner or contractor to significant legal liability. When
underground facilities are damaged and/or when property damage or
personal injury results from damaging an underground facility during an
excavation, the excavator may assert that the facility was not accurately
located and/or marked by a locate technician, while the locate contractor
who dispatched the technician may in turn assert that the facility was
indeed properly located and marked. Proving whether the underground
facility was properly located and marked can be difficult after the
excavation (or after some damage, e.g., a gas explosion), because in many
cases the physical locate marks (e.g., the marking material or other
physical marks used to mark the facility on the surface of the dig area)
will have been disturbed or destroyed during the excavation process
(and/or damage resulting from excavation).

[0026]Previous efforts at documenting locate operations have focused
primarily on locate devices that employ electromagnetic fields to
determine the presence of an underground facility. For example, U.S. Pat.
No. 5,576,973, naming inventor Alan Haddy and entitled "Apparatus and
Method for Obtaining Geographical Positional Data for an Object Located
Underground" (hereafter "Haddy"), is directed to a locate device (i.e., a
"locator") that receives and stores data from a global positioning system
("GPS") to identify the position of the locate device as an underground
object (e.g., a cable) is detected by the locate device. Haddy notes that
by recording geographical position data relating to the detected
underground object, there is no need to physically mark the location of
the underground object on the ground surface, and the recorded position
data may be used in the future to re-locate the underground object.

[0027]Similarly, U.S. Pat. No. 7,319,387, naming inventors Willson et al.
and entitled "GPS Interface for Locating Device" (hereafter "Willson"),
is directed to a locate device for locating "position markers," i.e.,
passive antennas that reflect back RF signals and which are installed
along buried utilities. In Willson, a GPS device may be communicatively
coupled to the locate device, or alternatively provided as an integral
part of the locate device, to store GPS coordinate data associated with
position markers detected by the locate device. Electronic memory is
provided in the locate device for storing a data record of the GPS
coordinate data, and the data record may be uploaded to a remote computer
and used to update a mapping database for utilities.

[0028]U.S. Publication No. 2006/0282280, naming inventors Stotz et al. and
entitled "Ticket and Data Management" (hereafter "Stotz"), also is
directed to a locate device (i.e., a "locator") including a GPS receiver.
Upon detection of the presence of a utility line, Stotz' locate device
can update ticket data with GPS coordinates for the detected utility
line. Once the locate device has updated the ticket data, the
reconfigured ticket data may be transmitted to a network.

[0029]U.S. Publication No. 2007/0219722, naming inventors Sawyer, Jr. et
al. and entitled "System and Method for Collecting and Updating
Geographical Data" (hereafter "Sawyer"), is directed to collecting and
recording data representative of the location and characteristics of
utilities and infrastructure in the field for creating a grid or map.
Sawyer employs a field data collection unit including a "locating pole"
that is placed on top of or next to a utility to be identified and added
to the grid or map. The locating pole includes an antenna coupled to a
location determination system, such as a GPS unit, to provide
longitudinal and latitudinal coordinates of the utility under or next to
the end of the locating pole. The data gathered by the field data
collection unit is sent to a server to provide a permanent record that
may be used for damage prevention and asset management operations.

SUMMARY

[0030]Applicants have recognized and appreciated that uncertainties which
may be attendant to locate and marking operations may be significantly
reduced by collecting various information particularly relating to the
marking operation, rather than merely focusing on information relating to
detection of underground facilities via a locate device. In many
instances, excavators arriving to a work site have only physical locate
marks on which to rely to indicate a presence or absence of underground
facilities, and they are not generally privy to information that may have
been collected previously during the locate operation. Accordingly, the
integrity and accuracy of the physical locate marks applied during a
marking operation arguably is significantly more important in connection
with reducing risk of damage and/or injury during excavation than the
location of where an underground facility was detected via a locate
device during a locate operation.

[0031]More specifically, Applicants have recognized and appreciated that
conventional techniques for using a locate device to detect underground
facilities are sometimes tentative and typically iterative in nature, and
use of locate devices with GPS capabilities may result in redundant,
spurious and/or incomplete geographic location data collected by such
devices. For example, during a typical locate operation, a technician
attempting to locate an underground facility with a locate device often
needs to sweep an appreciable area around a suspected underground
facility, and make multiple passes with the locate device over the
underground facility to obtain meaningful detection signals. Furthermore,
the technician often needs to rely significantly on visual observations
of the area, including relevant landmarks such as facility connections to
buildings, transformer boxes, maintenance/public access points, curbs,
sidewalks, roadways, etc., to effectively deduce a sensible path of an
underground facility to be located. The foregoing is particularly true if
at some point during the locate operation the technician loses a signal
from an underground facility in the process of being detected (e.g., due
to a broken transmitter circuit path from a damaged tracer wire, and loss
of the transmitter test signal). In view of the foregoing, it may be
readily appreciated that collecting and logging geographic location
information throughout this process may result in excessive and/or
imprecise data, or in some instances incomplete relevant data (e.g., in
the case of signal loss/broken tracer wire), from which it may be
difficult to cull the data that is truly complete and representative of
where the underground facility ultimately was detected.

[0032]Furthermore, Applicants have recognized and appreciated that the
location at which an underground facility ultimately is detected during a
locate operation is not always where the technician physically marks the
ground, pavement or other surface during a marking operation; in fact,
technician imprecision or negligence, as well as various ground
conditions and/or different operating conditions amongst different locate
device, may in some instances result in significant discrepancies between
detected location and physical locate marks. Accordingly, having
documentation (e.g., an electronic record) of where physical locate marks
were actually dispensed (i.e., what an excavator encounters when arriving
to a work site) is notably more relevant to the assessment of liability
in the event of damage and/or injury than where an underground facility
was detected prior to marking.

[0033]Examples of marking devices configured to collect some types of
information relating specifically to marking operations are provided in
U.S. publication no. 2008-0228294-A1, published Sep. 18, 2008, filed Mar.
13, 2007, and entitled "Marking System and Method With Location and/or
Time Tracking," and U.S. publication no. 2008-0245299-A1, published Oct.
9, 2008, filed Apr. 4, 2007, and entitled "Marking System and Method,"
both of which publications are incorporated herein by reference. These
publications describe, amongst other things, collecting information
relating to the geographic location, time, and/or characteristics (e.g.,
color/type) of dispensed marking material from a marking device and
generating an electronic record based on this collected information.
Applicants have recognized and appreciated that collecting information
relating to both geographic location and color of dispensed marking
material provides for automated correlation of geographic information for
a locate mark to facility type (e.g., red=electric power lines and
cables; blue=portable water; orange=telecommunication lines; yellow=gas,
oil, steam); in contrast, in conventional locate devices equipped with
GPS capabilities as discussed above, there is no apparent automated
provision for readily linking GPS information for a detected facility to
the type of facility detected. Applicants have further appreciated that
building a more comprehensive electronic record of information relating
to marking operations further facilitates ensuring the accuracy of such
operations.

[0034]In view of the foregoing, various embodiments of the present
invention are directed to marking apparatus with enhanced features, and
associated methods and systems, to facilitate collection of a wide
variety of information relating to a marking operation, and provide for
creation of a comprehensive and robust electronic record of a marking
operation. Marking information relating to use of a marking device to
perform a marking operation may be acquired from one or more of a variety
of input devices in any of a variety of manners, logged/stored in local
memory of a marking device, formatted in various manners, processed
and/or analyzed at the marking device itself, and/or transmitted to
another device (e.g., a remote computer/server) for storage, processing
and/or analysis.

[0035]In some exemplary embodiments described in detail herein, a marking
device may include one or more environmental sensors and/or operational
sensors, and the marking information may include environmental
information and operational information derived from such sensors.
Environmental and/or operational information may be used to control
operation of the marking device, assess out-of-tolerance conditions in
connection with use of the marking device, and/or provide alerts or other
feedback. In yet other embodiments, additional enhancements are disclosed
relating to improving the determination of a location (e.g., GPS
coordinates) of a dispensing tip of the marking device during use.

[0036]In other embodiments, a marking device may be operated in a "solo"
mode or a "group" mode. In particular, in a "solo" mode, the marking
device may be operated as an individual, independent device to collect,
store and/or transmit data, whereas in "group" mode, a marking device may
act as a "worker" device or a "leader" device to facilitate consolidation
of data collected by multiple devices (e.g., relating to a same ticket)
at a single one of the devices, at a host server, or at any other
suitable location.

[0037]In yet other embodiments, a marking device may be equipped with an
enhanced user interface having tactile functionality; in particular, the
marking device may include one or more tactile indicators (e.g.,
vibrating devices) disposed, for example, in a handle, joy stick,
actuator or elsewhere on the device, to provide a tactile indication to a
technician using the marking device (e.g., as feedback in connection with
an operating mode, operating condition, environmental condition, etc.).

[0038]During and/or following collection and/or storage of information
regarding the marking operation, data compiled in one or more electronic
records associated with the marking operation may be accessed, processed
and/or analyzed to provide further information relating to the
performance of the marking operation. For example, in other embodiments
disclosed herein, data from one or more electronic records of the marking
operation is processed so as to electronically render (visually recreate)
the marking operation (e.g., on a display device associated with the
marking device or other display device). Electronic renderings may be
generated statically (e.g., in which all available data in an electronic
record is rendered essentially simultaneously on an available display
field) or in an "animated" time-sequenced recreation of the marking
operation (e.g., based on at least timing and geographic location
information in the electronic record) once an electronic record is
generated. In yet another exemplary implementation, various information
to be logged in an electronic record may be passed/transmitted in
essentially real-time to one or more display devices to facilitate an
essentially real-time electronic rendering on an available display field
of a marking operation in process.

[0039]According to one embodiment of the present invention, a marking
apparatus for use in performing a marking operation to indicate a
presence or an absence of at least one underground facility is provided.
The marking apparatus comprises a hand-held housing, at least one
processor disposed within the hand-held housing, a holder configured to
hold to the hand-held housing at least one marking dispenser containing a
marking material, and at least one input device communicatively coupled
to the at least one processor and configured to sense at least one
environmental condition of an environment in which the marking apparatus
is located. The at least one input device is configured to provide an
output signal to the at least one processor indicative of the sensed at
least one environmental condition.

[0040]Another embodiment of the present invention is directed to a marking
apparatus for use in performing a marking operation to indicate a
presence or an absence of at least one underground facility. The marking
apparatus comprises a hand-held housing, at least one processor disposed
within the hand-held housing, a holder configured to hold to the
hand-held housing at least one marking dispenser containing a marking
material, and at least one actuator configured to actuate the marking
dispenser to dispense the marking material. The marking apparatus further
comprises a location tracking system configured to determine a location
of the apparatus, a temperature sensor communicatively coupled to the at
least one processor and configured to sense an ambient temperature of an
environment in which the marking apparatus is located and provide a first
output signal indicative of the ambient temperature to the at least one
processor, and a humidity sensor communicatively coupled to the at least
one processor and configured to sense humidity of the environment in
which the marking apparatus is located and provide a second output signal
indicative of the humidity to the at least one processor. The at least
one processor is programmed with processor-executable instructions which,
when executed, cause the at least one processor to compare the first
output signal to a target ambient temperature range for dispensing the
marking material and the second output signal to a target humidity range
for dispensing the marking material. In response to determining that one
or both of the first output signal and the second output signal is
indicative of an out-of-range ambient temperature and/or out-of-range
humidity, the at least one processor does at least one of (i) generate an
alert to a technician using the marking apparatus and (ii) disable the at
least one actuator.

[0041]Another embodiment of the present invention is directed to a method
for performing a marking operation to mark a presence or absence of at
least one underground facility using a marking device. The method
comprises A) dispensing, via actuation of an actuation system of the
marking device, marking material onto a target surface, B) detecting, via
at least one input device of the marking device, at least one
environmental condition of an environment in which the marking device is
located, and C) logging into local memory of the marking device marking
information relating at least in part to A) and B).

[0042]Another embodiment of the present invention is directed to an
apparatus for marking a presence or absence of an underground facility.
The apparatus comprises at least one actuator to control dispensing of a
marking material for marking the presence or absence of the underground
facility. The apparatus further comprises a memory to store
processor-executable instructions, at least one communication interface,
and at least one processor communicatively coupled to the at least one
actuator, the memory, and the at least one communication interface. Upon
execution of the processor-executable instructions, the processor
controls the at least one communication interface to receive
environmental information regarding at least one environmental condition
of an environment in which the apparatus is located, and stores at least
some of the received environmental information in the memory.

[0043]Another embodiment of the present invention is directed to a marking
apparatus for use in performing a marking operation to indicate a
presence or an absence of at least one underground facility, comprising a
hand-held housing and at least one processor disposed within the
hand-held housing. The marking apparatus further comprises a holder
configured to hold to the hand-held housing at least one marking
dispenser containing a marking material, a location tracking system
configured to determine a location of the apparatus, and at least one
input device communicatively coupled to the at least one processor and
configured to sense an operating condition of the apparatus and provide
an output signal to the at least one processor indicative of the sensed
operating condition.

[0044]Another embodiment of the present invention is directed to a marking
apparatus for use in performing a marking operation to indicate a
presence or an absence of at least one underground facility. The marking
apparatus comprises a housing, at least one processor disposed within the
housing, a holder configured to hold to the housing at least one marking
dispenser containing a marking material, and at least one actuator
configured to actuate the marking dispenser to dispense the marking
material. The marking apparatus further comprises an input device
communicatively coupled to the at least one processor to provide an input
signal to the at least one processor. The at least one processor is
programmed with processor-executable instructions which, when executed,
cause the at least one processor to compare the input signal to a target
value or range of values to assess whether an out-of-tolerance condition
is indicated by the input signal. If an out-of-tolerance condition is
indicated by the input signal, the at least one processor does at least
one of: (a) log an out-of-tolerance indication into an electronic record;
(b) generate an alert to a user of the marking apparatus that an
out-of-tolerance condition has been detected; and (c) disable the at
least one actuator.

[0045]Another embodiment of the present invention is directed to a method
for use of a marking device, the marking device for use in performing a
marking operation to indicate a presence or an absence of at least one
underground facility. The method comprises A) acquiring, using an
environmental sensor of the marking device, environmental information
representative of at least one environmental condition of an environment
in which the marking device is located. The method further comprises B)
dispensing a marking material using a marking dispenser of the marking
device to mark the presence or the absence of the at least one
underground facility. The method further comprises C) controlling B)
based at least in part on the environmental information acquired in A).

[0046]Another embodiment of the present invention is directed to a method
for use of a marking device, the marking device for use in performing a
marking operation to indicate a presence or an absence of at least one
underground facility. The method comprises A) acquiring, using an
environmental sensor of the marking device, environmental information
representative of at least one environmental condition of an environment
in which the marking device is located. The method further comprises B)
comparing the environmental information to a target value or range of
values to assess whether an out-of-tolerance condition with respect to
the environment is indicated by the environmental information. The method
further comprises C) if an out-of-tolerance condition is indicated, doing
at least one of: (i) logging an out-of-tolerance indication into an
electronic record; (ii) generating an alert to a user of the marking
apparatus that an out-of-tolerance condition has been detected; and (iii)
controlling dispensing of marking material by the marking device.

[0047]Another embodiment of the present invention is directed to a method
for using a marking device, the marking device for use in performing a
marking operation to indicate a presence or an absence of at least one
underground facility. The method comprises A) acquiring, using an
operational sensor of the marking device, operating information
representative of at least one operating condition of the marking device.
The method further comprises B) dispensing a marking material using a
marking dispenser of the marking device to mark the presence or the
absence of the at least one underground facility. The method further
comprises C) controlling B) based at least in part on the operating
information acquired in A).

[0048]Another embodiment of the present invention is directed to a method
for using operational data collected as part of a marking operation to
indicate the presence or absence of an underground facility. The method
comprises receiving the operational data representative of an operating
condition of a marking device used to perform the marking operation, and
analyzing the operational data for an operating pattern of a technician
using the marking device.

[0049]Another embodiment of the present invention is directed to at least
one computer-readable storage medium storing an electronic record
associated with a marking operation. The electronic record comprises at
least one data set representing a technician signature with respect to a
technician's operation of a marking device for performing the marking
operation.

[0050]Another embodiment of the present invention is directed to a marking
apparatus for performing a marking operation to mark on ground, pavement,
or other surface a presence or an absence of at least one underground
facility. The apparatus comprises an actuator to dispense a marking
material so as to form at least one locate mark on the ground, pavement
or other surface to mark the presence or the absence of the at least one
underground facility. The apparatus further comprises at least one input
device to provide marking information regarding the marking operation.
The at least one input device is configured to sense at least one
environmental condition of an environment in which the apparatus is
located and provide an output signal indicative of the sensed at least
one environmental condition. The apparatus further comprises at least one
processor communicatively coupled to the actuator and the at least one
input device so as to receive the output signal. In one implementation,
the apparatus further comprises a memory to store processor-executable
instructions. The marking information includes environmental information
represented at least in part by the output signal indicative of the
sensed at least one environmental condition. In one aspect of this
implementation, upon execution of the processor-executable instructions,
the processor logs into the memory at least some of the environmental
information. In another aspect, the processor logs into the memory the at
least some of the environmental information based at least in part on at
least one actuation of the actuator.

[0051]For purposes of the present disclosure, the term "dig area" refers
to a specified area of a work site within which there is a plan to
disturb the ground (e.g., excavate, dig holes and/or trenches, bore,
etc.), and beyond which there is no plan to excavate in the immediate
surroundings. Thus, the metes and bounds of a dig area are intended to
provide specificity as to where some disturbance to the ground is planned
at a given work site. It should be appreciated that a given work site may
include multiple dig areas.

[0052]The term "facility" refers to one or more lines, cables, fibers,
conduits, transmitters, receivers, or other physical objects or
structures capable of or used for carrying, transmitting, receiving,
storing, and providing utilities, energy, data, substances, and/or
services, and/or any combination thereof. The term "underground facility"
means any facility beneath the surface of the ground. Examples of
facilities include, but are not limited to, oil, gas, water, sewer,
power, telephone, data transmission, cable television (TV), and/or
internet services.

[0053]The term "locate device" includes one or both of a locate
transmitter and a locate receiver (which in some instances may also be
referred to collectively as a "locate instrument set," or simply "locate
set").

[0054]The term "marking device" refers to any apparatus, mechanism, or
other device that employs a marking dispenser for causing a marking
material and/or marking object to be dispensed, or any apparatus,
mechanism, or other device for electronically indicating (e.g., logging
in memory) a location, such as a location of an underground facility.
Additionally, the term "marking dispenser" refers to any apparatus,
mechanism, or other device for dispensing and/or otherwise using,
separately or in combination, a marking material and/or a marking object.
An example of a marking dispenser may include, but is not limited to, a
pressurized can of marking paint. The term "marking material" means any
material, substance, compound, and/or element, used or which may be used
separately or in combination to mark, signify, and/or indicate. Examples
of marking materials may include, but are not limited to, paint, chalk,
dye, and/or iron. The term "marking object" means any object and/or
objects used or which may be used separately or in combination to mark,
signify, and/or indicate. Examples of marking objects may include, but
are not limited to, a flag, a dart, and arrow, and/or an RFID marking
ball. It is contemplated that marking material may include marking
objects. It is further contemplated that the terms "marking materials" or
"marking objects" may be used interchangeably in accordance with the
present disclosure.

[0055]The term "locate mark" means any mark, sign, and/or object employed
to indicate the presence or absence of any underground facility. Examples
of locate marks may include, but are not limited to, marks made with
marking materials, marking objects, global positioning or other
information, and/or any other means. Locate marks may be represented in
any form including, without limitation, physical, visible, electronic,
and/or any combination thereof.

[0056]The terms "actuate" or "trigger" (verb form) are used
interchangeably to refer to starting or causing any device, program,
system, and/or any combination thereof to work, operate, and/or function
in response to some type of signal or stimulus. Examples of actuation
signals or stimuli may include, but are not limited to, any local or
remote, physical, audible, inaudible, visual, non-visual, electronic,
mechanical, electromechanical, biomechanical, biosensing or other signal,
instruction, or event. The terms "actuator" or "trigger" (noun form) are
used interchangeably to refer to any method or device used to generate
one or more signals or stimuli to cause or causing actuation. Examples of
an actuator/trigger may include, but are not limited to, any form or
combination of a lever, switch, program, processor, screen, microphone
for capturing audible commands, and/or other device or method. An
actuator/trigger may also include, but is not limited to, a device,
software, or program that responds to any movement and/or condition of a
user, such as, but not limited to, eye movement, brain activity, heart
rate, other data, and/or the like, and generates one or more signals or
stimuli in response thereto. In the case of a marking device or other
marking mechanism (e.g., to physically or electronically mark a facility
or other feature), actuation may cause marking material to be dispensed,
as well as various data relating to the marking operation (e.g.,
geographic location, time stamps, characteristics of material dispensed,
etc.) to be logged in an electronic file stored in memory. In the case of
a locate device or other locate mechanism (e.g., to physically locate a
facility or other feature), actuation may cause a detected signal
strength, signal frequency, depth, or other information relating to the
locate operation to be logged in an electronic file stored in memory.

[0057]The terms "locate and marking operation," "locate operation," and
"locate" generally are used interchangeably and refer to any activity to
detect, infer, and/or mark the presence or absence of an underground
facility. In some contexts, the term "locate operation" is used to more
specifically refer to detection of one or more underground facilities,
and the term "marking operation" is used to more specifically refer to
using a marking material and/or one or more marking objects to mark a
presence or an absence of one or more underground facilities. The term
"locate technician" refers to an individual performing a locate
operation. A locate and marking operation often is specified in
connection with a dig area, at least a portion of which may be excavated
or otherwise disturbed during excavation activities.

[0058]The term "user" refers to an individual utilizing a locate device
and/or a marking device and may include, but is not limited to, land
surveyors, locate technicians, and support personnel.

[0059]The terms "locate request" and "excavation notice" are used
interchangeably to refer to any communication to request a locate and
marking operation. The term "locate request ticket" (or simply "ticket")
refers to any communication or instruction to perform a locate operation.
A ticket might specify, for example, the address or description of a dig
area to be marked, the day and/or time that the dig area is to be marked,
and/or whether the user is to mark the excavation area for certain gas,
water, sewer, power, telephone, cable television, and/or some other
underground facility. The term "historical ticket" refers to past tickets
that have been completed.

[0094]It should be appreciated that all combinations of the foregoing
concepts and additional concepts discussed in greater detail below
(provided such concepts are not mutually inconsistent) are contemplated
as being part of the inventive subject matter disclosed herein. In
particular, all combinations of claimed subject matter appearing at the
end of this disclosure are contemplated as being part of the inventive
subject matter disclosed herein. It should also be appreciated that
terminology explicitly employed herein that also may appear in any
disclosure incorporated by reference should be accorded a meaning most
consistent with the particular concepts disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0095]FIGS. 1A and 1B illustrate a conventional marking device in an
actuated and non-actuated state, respectively;

[0096]FIG. 2 is a functional block diagram of a data acquisition system
according to one embodiment of the present invention for creating
electronic records of marking operations based on actuations of a marking
device;

[0097]FIG. 3 is a perspective view of the data acquisition system of FIG.
2, illustrating an exemplary marking device according to one embodiment
of the present invention;

[0098]FIGS. 4A and 4B illustrate a portion of an actuation system of the
marking device of FIG. 3 according to one embodiment of the present
invention;

[0099]FIG. 5 illustrates various components of an actuation system 120
according to other embodiments of the present invention;

[0100]FIG. 6 is a perspective view of an exemplary marking device being
used for marking a dotting pattern, according to one embodiment of the
present invention;

[0101]FIG. 7 is a perspective view of an exemplary marking device being
used for marking a lines pattern, according to one embodiment of the
present invention;

[0102]FIG. 8 is a plan view that shows further details of the lines
pattern of FIG. 7, in connection with the information acquired for
purposes of creating an electronic record according to one embodiment of
the present invention;

[0103]FIG. 9 is a flow diagram of an exemplary method for collecting
marking information for generation of an electronic record, according to
one embodiment of the present invention;

[0104]FIG. 10 is a block diagram of an exemplary data structure for an
electronic record of a marking operation including information retrieved
during one or more actuations of a marking device, according to one
embodiment of the present invention;

[0105]FIGS. 11A and 11B conceptually illustrate a portion of an actuation
system of a marking device including a mechanical coupler, in which the
marking device has been modified to accommodate a landmark mode,
according to one embodiment of the present invention;

[0106]FIG. 12 is a flow diagram of an exemplary method for operating a
marking device having a marking mode and a landmark mode so as to collect
marking information and/or environmental landmark information, and
generate an electronic record of such information, according to one
embodiment of the present invention;

[0107]FIG. 13 is a block diagram of an exemplary data structure for an
electronic record of a marking operation including both marking
information and landmark information retrieved during actuations of a
marking device, according to one embodiment of the present invention;

[0108]FIG. 14 is a flow diagram of an exemplary method for displaying a
visual representation of a marking operation in a display field having a
predetermined scale, according to one embodiment of the present
invention;

[0109]FIG. 15 is an example of a visual representation showing electronic
locate marks and identifiers for environmental landmarks based on
collected data corresponding to respective actuations of a marking device
during marking operations, according to one embodiment of the present
invention;

[0110]FIG. 16 is an example of another visual representation of marking
operations, according to one embodiment of the present invention;

[0111]FIG. 17 is an example of another visual representation of marking
operations, according to another embodiment of the present invention, in
which electronic locate marks and identifiers for environmental landmarks
are overlaid on a digital image of a work site/dig area;

[0112]FIG. 18 shows a generic display device having a display field in
which one or more display layers and/or sub-layers of marking
information, landmark information, and/or image/reference information may
be selectively enabled or disabled for display, according to one
embodiment of the present invention;

[0113]FIG. 19 is a functional block diagram of a data acquisition system
including a marking device with both environmental sensors and
operational sensors, according to one embodiment of the present
invention;

[0114]FIG. 20 is a block diagram showing details of the environmental
sensors shown in FIG. 19, according to one embodiment of the present
invention;

[0115]FIG. 21 is a block diagram showing details of the operational
sensors shown in FIG. 19, according to one embodiment of the present
invention;

[0116]FIG. 22 is a functional block diagram of the marking device of FIG.
19, according to one embodiment of the present invention;

[0117]FIG. 23 is a perspective view illustrating a non-limiting physical
configuration of the marking device of FIG. 22, according to one
embodiment of the present invention;

[0118]FIG. 24 is a block diagram of an exemplary data structure of an
electronic record of a marking operation including information received
from environmental sensors and operational sensors of the marking device,
according to one embodiment of the present invention;

[0119]FIG. 25 illustrates a functional block diagram of an example of an
operations monitoring application for monitoring the use of locating
equipment such as a marking device, according to one embodiment of the
present invention;

[0120]FIG. 26 illustrates a functional block diagram of an example of a
locate operations system including the operations monitoring application
of FIG. 25, according to one embodiment of the present invention;

[0121]FIG. 27 illustrates a method of operation of a locate operations
system including an operations monitoring application, according to one
embodiment of the present invention;

[0122]FIG. 28 is a schematic diagram illustrating a configuration for
determining the difference in location between two points of a marking
device;

[0123]FIG. 29 illustrates a marking pattern that may be made by a
technician using a marking device according to various of the embodiments
described herein;

[0124]FIG. 30 illustrates a portion of a marking device including tactile
indicators, according to one embodiment of the present invention.

DETAILED DESCRIPTION

[0125]Following below are more detailed descriptions of various concepts
related to, and embodiments of, inventive marking apparatus having
enhanced features for underground facility marking operations, and
associated methods and systems. It should be appreciated that various
concepts introduced above and discussed in greater detail below may be
implemented in any of numerous ways, as the disclosed concepts are not
limited to any particular manner of implementation. Examples of specific
implementations and applications are provided primarily for illustrative
purposes.

I. OVERVIEW

[0126]In some embodiments of the present invention, a marking device
employed by a locate technician to dispense marking material is
particularly configured to acquire "marking information" relating to a
marking operation based at least in part on actuations of the marking
device, and create an electronic record of at least some of the marking
information. As discussed in greater detail below, examples of marking
information relating to the marking operation that may be logged into an
electronic record may include, but are not limited to: [0127]timing
information (e.g., one or more time stamps) associated with one or more
actuations of the marking device and/or one or more events occurring
during a given actuation; [0128]geographic information (e.g., one or more
geographic coordinates) associated with one or more actuations of the
marking device (in some instances, the geographic information may be
accompanied by timing information, such as a time stamp, for each
acquisition of geographic information); [0129]marking material
information: one or more aspects/characteristics of a marking material
(e.g., a color, brand, type, serial number, UPC code, weight, inventory
information, etc. associated with the marking material) dispensed in
response to one or more actuations of the marking device;
[0130]service-related information: one or more identifiers for the locate
technician performing the marking operation, the marking device itself
(e.g., a serial number of the marking device), and/or the locate
contractor dispatching the locate technician; [0131]ticket information:
information relating to one or more facilities to be marked, location
information (e.g., an address, geo-coordinates, and/or text description)
relating to the work site and/or dig area in which the locate and marking
operation is performed, ground type information (e.g., a description of
the ground at which marking material is dispensed), excavator
information, other text-based information, etc.; [0132]environmental
information: information derived from one or more environmental sensors
associated with the marking device, examples of which sensors include,
but are not limited to, temperature sensors, humidity sensors, light
sensors, altitude sensors, image capture devices and audio recorders;
[0133]operational information: information derived from one or more
operational sensors associated with the marking device, examples of which
sensors include, but are not limited to, operational temperature sensors,
a compass, an inclinometer, an accelerometer, a yaw rate sensor, a
proximity sensor, a pressure sensor, one or more device health sensors,
image capture devices, and audio devices; and [0134]device health
information: information about the status of one or more components of a
locate device, such as battery status, WiFi connectivity status, GPS
receiver status (e.g., GPS signal strength/quality, number of satellites
in view), etc.

[0135]Marking information including any or all of the foregoing types of
information may be logged/stored in local memory of a marking device,
formatted in various manners, processed and/or analyzed at the marking
device itself, and/or transmitted to another device (e.g., a remote
computer/server) for storage, processing and/or analysis. In particular,
environmental and/or operational information may be used to control
operation of the marking device, assess out-of-tolerance conditions in
connection with use of the marking device, and/or provide alerts or other
feedback. In yet other embodiments, operational information may be
analyzed and processed so as to improve a determination of a location
(e.g., GPS coordinates) of a dispensing tip of the marking device during
use.

[0136]In other embodiments, a marking device may be configured to operate
in multiple different modes so as to collect various information relating
not only to a marking operation itself, but additionally (or
alternatively) various information relating to the work site/dig area in
which the marking operation is performed. For example, in one
implementation, the marking device may be configured to operate in a
first "marking mode" as well as a second "landmark identification mode"
(or more simply "landmark mode"). In a "marking mode," marking material
may be dispensed with respective actuations of the marking device and
various marking information transmitted and/or stored in an electronic
record attendant to this process. Alternatively, in a "landmark mode,"
marking material is not necessarily dispensed with an actuation of the
marking device (and in some instances the dispensing of marking material
is specifically precluded); instead, a technician positions the marking
device proximate to an environmental landmark of interest and, upon
actuation, the marking device collects various information about the
landmark (hereafter referred to as "landmark information"). As discussed
in greater detail below, landmark information may include, but is not
limited to, geo-location data of an environmental landmark, type of
environmental landmark, and a time stamp for any acquired information
relating to an environmental landmark.

[0137]In other embodiments, a marking device may be operated in a "solo"
mode or a "group" mode. In particular, in a "solo" mode, the marking
device may be operated as an individual, independent device to collect,
store and/or transmit data, whereas in "group" mode, a marking device may
act as a "worker" device or a "leader" device to facilitate consolidation
of data collected by multiple devices (e.g., relating to a same ticket)
to a host server.

[0138]In yet other embodiments, a marking device may be equipped with an
enhanced user interface having tactile functionality; in particular, the
marking device may include one or more tactile indicators (e.g.,
vibrating devices) disposed, for example, in a handle, joy stick,
actuator or elsewhere on the device, to provide a tactile indication to a
technician using the marking device (e.g., as feedback in connection with
an operating mode, operating condition, environmental condition, etc.).

[0139]In various implementations of the methods and apparatus described
herein, data from one or more electronic records, including one or more
pieces of marking information and/or one or more pieces of landmark
information, may be processed and analyzed to provide insight into the
marking operation. In one embodiment, a computer-generated image or other
visual representation based on the marking information and/or landmark
information may be electronically rendered; for example, this visual
representation may provide electronic indications ("electronic locate
marks") of the relative placement of marking material dispensed during a
marking operation, and electronic locate marks corresponding to different
types of facilities may be color-coded. Additionally, electronic
identifiers (e.g., icons, shapes, symbols, patterns, etc.) of one or more
environmental landmarks may be included in a visual representation, alone
or together with electronic locate marks. Such a visual representation
may be used, for example, to provide immediate feedback to the locate
technician (e.g., via a display device associated with the marking
device), provide essentially real-time feedback to a supervisor
monitoring the technician's work from a remote location, provide a visual
record of the marking information and/or landmark information (e.g., for
archiving purposes once one or more electronic records are generated),
and/or to verify the quality (e.g., accuracy and completeness) of work
performed during a locate and marking operation.

II. MARKING DEVICE

[0140]FIGS. 2 and 3 illustrate a functional block diagram and perspective
view, respectively, of one example of a data acquisition system 100,
including a marking device 110 and optionally a remote computer 150,
according to one embodiment of the present invention. One or both of the
marking device 110 and the remote computer 150 of the data acquisition
system 100 may be configured to sense one or more actuations of the
marking device 110 (e.g., to dispense marking material during a marking
operation), and collect information based on one or more actuations of
the marking device so as to generate an electronic record.

[0141]As shown in FIG. 2, in one embodiment marking device 110 includes
control electronics 112, the components of which are powered by a power
source 114. Power source 114 may be any power source that is suitable for
use in a portable device, such as, but not limited to, one or more
rechargeable batteries, one or more non-rechargeable batteries, a solar
photovoltaic panel, a standard AC power plug feeding an AC-to-DC
converter, and the like.

[0142]The marking device 110 is configured to hold a marking dispenser
116, which as shown in FIG. 3 is loaded into a marking material holder
140 of the marking device 110. In one exemplary implementation, the
marking dispenser 116 is an aerosol paint canister that contains paint;
however, it should be appreciated that the present invention is not
limited in this respect, as a marking material dispensed by the marking
device 110 may be any material, substance, compound, and/or element, used
to mark, signify, and/or indicate. Examples of marking materials may
include, but are not limited to, paint, chalk, dye, and/or marking
powder.

[0143]As also shown in FIG. 2, in one embodiment control electronics 112
of marking device 110 may include, but are not limited to, a processor
118, at least a portion of an actuation system 120 (another portion of
which may include one or more mechanical elements), a local memory 122, a
communication interface 124, a user interface 126, a timing system 128,
and a location tracking system 130.

[0144]The processor 118 may be any general-purpose processor, controller,
or microcontroller device. Local memory 122 may be any volatile or
non-volatile data storage device, such as, but not limited to, a random
access memory (RAM) device and a removable memory device (e.g., a
universal serial bus (USB) flash drive, a multimedia card (MMC), a secure
digital card (SD), a compact flash card (CF), etc.). As discussed further
below, the local memory may store a marking data algorithm 134, which may
be a set of processor-executable instructions that when executed by the
processor 118 causes the processor to control various other components of
the marking device 110 so as to generate an electronic record 135 of a
marking operation, which record also may be stored in the local memory
122 and/or transmitted in essentially real-time (as it is being
generated) or after completion of a marking operation to a remote device
(e.g., remote computer 150).

[0145]In one exemplary implementation, a Linux-based processing system for
embedded handheld and/or wireless devices may be employed in the marking
device 110 to implement various components of the control electronics
112. For example, the Fingertip4® processing system, including a
Marvell PXA270 processor and available from InHand Electronics, Inc.
(www.inhandelectronics.com/products/fingertip4), may be used. In addition
to the PXA270 processor (e.g., serving as the processor 118), the
Fingertip4® includes flash memory and SDRAM (e.g., serving as local
memory 122), multiple serial ports, a USB port, and other I/O interfaces
(e.g., to facilitate interfacing with one or more input devices and other
components of the marking device), supports a variety of wired and
wireless interfaces (WiFi, Bluetooth®, GPS, Ethernet, any IEEE 802.11
interface, or any other suitable wireless interface) to facilitate
implementation of the communication interface 124, and connects to a wide
variety of LCD displays (to facilitate implementation of a user
interface/display).

[0146]Communication interface 124 of marking device 110 may be any wired
and/or wireless communication interface by which information may be
exchanged between marking device 110 and an external or remote device,
such as a remote computing device that is elsewhere in the dig area
(i.e., not a part of the marking device 110) or outside the dig area. For
example, data that is provided by components of data acquisition system
100 and/or stored in local memory 122 (e.g., one or more electronic
records 135) may be transmitted via communication interface 124 to a
remote computer, such as remote computer 150, for processing. Examples of
wired communication interfaces may include, but are not limited to, USB
ports, RS232 connectors, RJ45 connectors, Ethernet, and any combination
thereof. Examples of wireless communication interfaces may include, but
are not limited to, an Intranet connection, Internet, Bluetooth®
technology, Wi-Fi, Wi-Max, IEEE 802.11 technology (e.g., operating at a
minimum bandwidth of 54 Mbps, or any other suitable bandwidth), radio
frequency (RF), Infrared Data Association (IrDA) compatible protocols,
Local Area Networks (LAN), Wide Area Networks (WAN), Shared Wireless
Access Protocol (SWAP), any combination thereof, and other types of
wireless networking protocols. The wireless interface may be capable of
capturing signals that reflect a user's intent. For example, the wireless
interface may include a microphone that can capture a user's intent by
capturing the user's audible commands. Alternatively, the wireless
interface may interact with a device that monitors a condition of the
user, such as eye movement, brain activity, and/or heart rate.

[0147]User interface 126 of marking device 110 may be any mechanism or
combination of mechanisms by which a user may operate data acquisition
system 100 and by which information that is generated by data acquisition
system 100 may be presented to the user. For example, user interface 126
may include, but is not limited to, a display device (including
integrated displays and external displays, such as Heads-Up Displays
(HUDs)), a touch screen, one or more manual pushbuttons, a microphone to
provide for audible commands, one or more light-emitting diode (LED)
indicators, one or more toggle switches, a keypad, an audio output (e.g.,
speaker, buzzer, and alarm), and any combination thereof. In one
implementation, the user interface 126 includes a "menu/on" button to
power up the marking device and provide a menu-driven graphical user
interface (GUI) displayed by the display device (e.g., menu items and/or
icons displayed on the display device) and navigated by the technician
via a joystick or a set of four "up/down/left/right" buttons, as well as
a "select/ok" button to take some action pursuant to the selection of a
menu item/icon. As described below, the display may also be used in some
embodiments of the invention to display information relating to a
placement of marking material in a dig area, a location of an underground
facility in a dig area, or any other suitable information that may be
displayed based on information acquired to create an electronic record
135.

[0148]In various embodiments, the one or more interfaces of the marking
device 110--including the communication interface 124 and user interface
126--may be used as input devices to receive information to be stored in
the memory 122 as part of an electronic record of a marking operation. In
some cases, marking information received via the interface(s) (e.g., via
the communication interface 124) may include ticket information regarding
underground facilities to be marked during a marking operation. As
another example, using an interface such as the user interface 126,
service-related information may be input, including an identifier for the
marking device used by the technician, an identifier for a technician,
and/or an identifier for the technician's employer. Alternatively, some
or all of the service-related information similarly may be received via
the communication interface 124 (and likewise some or all of the ticket
information may be received via the user interface 126).

[0149]The actuation system 120 of marking device 110 shown in the block
diagram of FIG. 2 may include both electrical and mechanical elements
according to various embodiments discussed in further detail below, and
for purposes of illustration is shown in FIG. 2 as included as part of
the control electronics 112. The actuation system 120 may include a
mechanical and/or electrical actuator mechanism (e.g., see the actuator
142 shown in FIG. 3) to provide one or more signals or stimuli as an
input to the actuation system 120. Upon receiving one or more signals or
stimuli (e.g., actuation/triggering by a locate technician or other
user), the actuation system 120 causes marking material to be dispensed
from marking dispenser 116. In various embodiments, the actuation system
120 may employ any of a variety of mechanical and/or electrical
techniques (e.g., one or more switches or other circuit components, a
dedicated processor or the processor 118 executing instructions, one or
more mechanical elements, various types of transmitters and receivers, or
any combination of the foregoing), as would be readily appreciated by
those of skill in the relevant arts, to cause the marking dispenser 116
to dispense marking material in response to one or more signals or
stimuli. The actuation system 120 also provides one or more output
signals in the form of an actuation signal 121 to the processor 118 to
indicate one or more actuations of the marking device, in response to
which the processor 118 may acquire/collect various marking information
and log data into the electronic record 135. Additional details of
exemplary actuation system implementations are provided below in
connection with FIGS. 3 through 5.

[0150]In some embodiments, the actuation system 120 may be configured so
as not to cause marking material to be dispensed from marking dispenser
116 in response to one or more signals or stimuli; rather, the actuation
system may merely facilitate a logging of data from one or more input
devices in response to operation of an actuator/trigger, without
necessarily dispensing marking material. In some instances, this may
facilitate "simulation" of a marking operation (i.e., simulating the
dispensing of marking material) by providing an actuation signal 121 to
the processor 118 indicating one or more simulated actuation events, in
response to which the processor may cause the logging of various data for
creating an electronic record without any marking material actually being
dispensed.

[0151]Location tracking system 130 of marking device 110 constitutes
another type of input device that provides marking information, and may
include any device that can determine its geographical location to a
certain degree of accuracy. For example, location tracking system 130 may
include a global positioning system (GPS) receiver or a global navigation
satellite system (GNSS) receiver. A GPS receiver may provide, for
example, any standard format data stream, such as a National Marine
Electronics Association (NMEA) data stream, or other data formats. An
error correction component 131 may be, but is not limited to, any
mechanism for improving the accuracy of the geographic information
provided by location tracking system 130; for example, error correction
component 131 may be an algorithm for correcting any offsets (e.g., due
to local disturbances in the atmosphere) in the geo-location data of
location tracking system 130. While shown as part of a local location
tracking system of the marking device 110, error correction component 131
alternatively may reside at a remote computing device, such as remote
computer 150. In other embodiments, location tracking system 130 may
include any device or mechanism that may determine location by any other
means, such as performing triangulation by use of cellular radiotelephone
towers.

[0152]In one exemplary implementation, the location tracking system 130
may include an ISM300F2-05-V0005 GPS module available from Inventek
Systems, LLC of Westford, Mass. (see
www.inventeksys.com/html/ism300f2-c5-v0005.html). The Inventek GPS module
includes two UARTs (universal asynchronous receiver/transmitter) for
communication with the processor 118, supports both the SIRF Binary and
NMEA-0183 protocols (depending on firmware selection), and has an
information update rate of 5 Hz. A variety of geographic location
information may be requested by the processor 118 and provided by the GPS
module to the processor 118 including, but not limited to, time
(coordinated universal time--UTC), date, latitude, north/south indicator,
longitude, east/west indicator, number and identification of satellites
used in the position solution, number and identification of GPS
satellites in view and their elevation, azimuth and SNR values, and
dilution of precision values. Accordingly, it should be appreciated that
in some implementations the location tracking system 130 may provide a
wide variety of geographic information as well as timing information
(e.g., one or more time stamps) to the processor 118.

[0153]In another embodiment, location tracking system 130 may not reside
locally on marking device 110. Instead, location tracking system 130 may
reside on any on-site computer, which serves as a location reference
point, to which the location of marking device 110 may be correlated by
any other means, such as, but not limited to, by a triangulation
technique between the on-site computer and marking device 110.

[0154]With respect to other input devices of the marking device 110 that
may provide marking information, the control electronics 112 may also
include a timing system 128 having an internal clock (not shown), such as
a crystal oscillator device, for processor 118. Additionally, timing
system 128 may include a mechanism for registering time with a certain
degree of accuracy (e.g., accuracy to the minute, second, or millisecond)
and may also include a mechanism for registering the calendar date. In
various implementations, the timing system 128 may be capable of
registering the time and date using its internal clock, or alternatively
timing system 128 may receive its time and date information from the
location tracking system 130 (e.g., a GPS system) or from an external
timing system, such as a remote computer or network, via communication
interface 124. In yet other implementations, a dedicated timing system
for providing timing information to be logged in an electronic record 135
may be optional, and timing information for logging into an electronic
record may be obtained from the location tracking system 130 (e.g., GPS
latitude and longitude coordinates with a corresponding time stamp).
Timing information may include, but is not limited to, a period of time,
timestamp information, date, and/or elapsed time.

[0155]Marking material detection mechanism 132 of the marking device 110
shown in FIG. 2 is another type of input device that provides marking
information, and may be any mechanism or mechanisms for determining a
presence or absence of a marking dispenser 116 in or otherwise coupled to
the marking device 110, as well as determining certain
attributes/characteristics of the marking material within marking
dispenser 116 when the dispenser is placed in or coupled to the marking
device. As shown in FIG. 3, in some embodiments the marking material
detection mechanism 132 may be disposed generally in an area proximate to
a marking material holder 140 in which a marking dispenser 116 may be
placed.

[0156]For example, in one embodiment, the marking material detection
mechanism 132 may include one or more switch devices (e.g., a make/break
single pole/single throw contact switch) disposed at one or more points
along the marking material holder 140 and electrically coupled to the
processor 118. The switch device(s) may also be coupled to ground or a DC
supply voltage, such that when the switch device is in a first state
(e.g., closed/making contact) the ground or DC supply voltage is passed
to the processor 118 (e.g., via an I/O pin of the processor which
provides an interrupt to, or is periodically monitored by, the
processor), and when the switch is in a second state (e.g., open/no
contact) the ground or DC supply voltage is not passed to the processor
118. When the marking dispenser 116 is present in the holder 140, the
switch device(s) is in one of two possible states and when there is no
marking dispenser the switch device(s) is in another of the two possible
states (e.g., the marking dispenser, when present, may depress the switch
device(s) so as to make contact and pass the ground/DC voltage to the
processor). In this manner, the marking material detection mechanism 132
may provide a signal to the processor indicating the presence or absence
of the marking dispenser 116 in the marking device 110.

[0157]The marking material detection mechanism 132 also or alternatively
may include a barcode reader to read barcode data from a dispenser 116
and/or a radio-frequency identification (RFID) reader for reading
information from an RFID tag that is provided on marking dispenser 116.
The RFID tag may include, for example, a unique serial number or
universal product code (UPC) that corresponds to the brand and/or type of
marking material in marking dispenser 116. The type of information that
may be encoded within the RFID tag on marking dispenser 116 may include
product-specific information for the marking material, but any
information of interest may be stored on an RFID tag. For example,
user-specific information and/or inventory-related information may be
stored on each RFID tag for a marking dispenser 116 to facilitate
inventory tracking of marking materials. In particular, an identifier for
a technician may be stored on an RFID tag when the technician is provided
with a marking dispenser 116, and information relating to weight, amount
dispensed, and/or amount remaining may be written to the RFID tag
whenever the marking dispenser is used.

[0158]In one exemplary implementation, the marking material detection
mechanism 132 may include a Micro RWD MIFARE-ICODE RFID reader module
available from IB Technology (Eccel Technology Ltd) of Aylesbury,
Buckinghamshire, UK (see www.ibtechnology.co.uk/products/icode.htm). The
Micro RWD reader module includes an RS232 communication interface to
facilitate communication between the processor 118 and the reader module
(e.g., via messages sent as a string of ASCII characters), and supports
both reading information from an RFID tag attached to a marking dispenser
as well as writing information to an RFID tag attached to the marking
dispenser. In one aspect of an exemplary implementation, an antenna
constituted by one or more turns of wire (e.g., two turns of awg 26 wire,
6.5 cm in diameter, about 1 uH) is coupled to the Micro RWD reader module
and disposed in the marking material holder 140 of the marking device 110
(see FIG. 3), proximate to a marking dispenser 116 when placed in the
holder 140, so as to capture close near field signals (e.g., from an RFID
tag on the dispenser, within about 2 inches) and exclude far field
signals. In another aspect, the Micro RWD reader module may be configured
to read RFID tags having an ICODE SLI format (e.g., ISO 15693 ICODE SLI).
In yet another aspect, an RFID tag may be affixed to an aerosol paint can
serving as the marking dispenser, such that the tag conforms to a plastic
cap of the paint can and is disposed at a particular location relative to
a notch in the cap (e.g., 90 degrees+/-15 degrees from the notch) that
allows access to the spray nozzle of the can and is in a relatively
predictable position substantially aligned with the antenna when the
paint can is placed in the marking material holder 140. Examples of RFID
tags suitable for this purpose are available from BCS Solutions, Inc.
(see www.bcssolutions.com/solutions/rfid) and include, but are not
limited to, the HF Bullseye Wet Inlay SLA Round 40.

[0159]In yet other embodiments, marking material detection mechanism 132
may alternatively or further be configured to detect properties of
marking material as it is dispensed. For example, the marking material
detection mechanism may include one or more of an optical sensor, an
olfactory sensor, an auditory sensor (e.g., a microphone), a weight
sensor, and any combination thereof. For example, in one embodiment an
optical sensor in the marking device may be used to identify the
composition and/or type of marking material in the marking dispenser by
analyzing light reflected by the material as it is dispensed. Similarly,
an olfactory sensor may be used to identify one or more characteristics
of the marking material based on an odor profile of the material, and an
auditory sensor may be used to identify the difference between paint
being sprayed from an aerosol can and aerosol without paint being sprayed
from a can (e.g., as the dispenser becomes emptied of paint).

[0160]In one embodiment, information provided by one or more input devices
of the marking device 110 (e.g., the timing system 128, the location
tracking system 130, the marking material detection mechanism 132, the
user interface 126, the communication interface 124) is acquired and
logged (stored in memory) upon actuation of the actuation system 120
(e.g., triggering an actuator). Some embodiments of the invention may
additionally or alternatively acquire/log information from one or more
input devices at one or more times during or throughout an actuation,
such as when a technician is holding a mechanical or electrical actuator
for some period of time and moving to dispense marking material in a line
(e.g., see FIG. 7). In various aspects of such embodiments, marking
information derived from one or more input devices may be collected at a
start time of an actuation, at one or more times during an actuation, and
in some cases at regular intervals during an actuation (e.g., several
times per second, once per second, once every few seconds). Further, some
marking information may be collected at an end of an actuation, such as
time information that may indicate a duration of an actuation.

[0161]Additionally, it should be appreciated that while some marking
information may be received via one or more input devices at the start of
each marking operation and upon successive actuations of the marking
device, in other cases some marking information may be collected by or
provided to the marking device once, prior to a marking operation (e.g.,
on power-up or reset of the marking device, as part of an electronic
instruction or dispatch by a locate company, and/or in response to a
request/query from a locate technician), and stored in local memory 122
for later incorporation into an electronic record. For example, prior to
a given marking operation and one or more actuations of the marking
device, ticket information and/or service-related information may have
already been received (e.g., via the communication interface 124 and/or
user interface 126) and stored in local memory 122. Upon generation of an
electronic record of a given marking operation, information previously
received via the interface(s) may be retrieved from the local memory (if
stored there initially) and entered into an electronic record, in some
case together with information collected pursuant to one or more
actuations of the marking device. Alternatively, ticket information
and/or service-related information may be received via the interface(s)
and stored in an entry in the electronic record 135 "directly" in
response to one or more actuations of the marking device (e.g., without
being first stored in local memory).

[0162]In sum, according to embodiments of the present invention, various
marking information from one or more input devices, regardless of how or
when it is received, may be stored in an electronic record of a marking
operation, in which at least some of the marking information is logged
pursuant to one or more actuations of the marking device.

[0163]In one embodiment, the optional remote computer 150 of the data
acquisition system 100 may be a centralized computer, such as a central
server of an underground facility locate service provider. In another
embodiment, remote computer 150 may be a computer that is at or near the
work site (i.e., "on-site"), e.g., a computer that is present in a locate
technician's vehicle.

[0164]Whether resident and/or executed on either the marking device 110 or
the remote computer 150, as noted above the marking data algorithm 134
includes a set of processor-executable instructions (e.g., stored in
memory, such as local memory 122 of the marking device) that, when
executed by processor 118 of the marking device 110 or another processor,
processes information (e.g., various marking information) collected in
response to (e.g., during) one or more actuations of the marking device
110, and/or in some cases before or after a given actuation or series of
actuations. As also discussed above, according to various embodiments the
actuations of marking device 110 may effect both dispensing marking
material and logging of marking information, or merely logging of marking
information for other purposes (e.g., simulating the dispensing of
marking material) without dispensing marking material. In either
situation, marking data algorithm 134, when executed by the processor
118, may cause the processor to perform collection, logging/storage
(creation of electronic records), and in some instances further
processing and analysis of various marking information with respect to
marking device actuations. For example, as discussed in further detail
below in connection with FIG. 9, the operations of marking data algorithm
134 as effected by the processor 118 may include, but are not limited to,
the following: [0165](1) reading in (acquiring) data that is generated
by any component (e.g., one or more input devices); for example, data may
be read in that is acquired at a start of a given actuation, throughout
the duration of the actuation, at the end of the actuation, before or
after the actuation, and any combination thereof; [0166](2) processing
the information that is collected and associating the collected
information with respective actuations; for example, any information
collected may be parsed/packaged so as to be associated with any one or
more actuations of the marking device, irrespective of when the data was
actually acquired; [0167](3) formatting the acquired information, e.g.,
as multiple time-stamped event entries constituting actuation data sets
forming an electronic record, wherein each actuation data set corresponds
to a particular actuation; and [0168](4) using respective actuation data
sets of an electronic record to visually recreate the marking operation
(e.g., render a computer-generated representation in a display field,
wherein respective actuation data sets correspond to electronic locate
marks).

[0169]It should also be appreciated that the marking data algorithm 134
may include one or more adjustable parameters that govern various aspects
of the collection and logging of marking information (e.g., the rate at
which various marking information is collected from one or more input
devices), and that these parameters may be adjusted or set, for example,
by an administrator at a remote computer, after which the marking data
algorithm is downloaded to the marking device for execution by the
processor 118. Alternatively, in other implementations, adjustable
parameters of a marking data algorithm already resident on a marking
device may in some cases be adjusted remotely via the communication
interface, or locally via the user interface.

[0170]While the functionality of various components of the marking device
110 was discussed above in connection with FIG. 2, FIG. 3 shows some
structural aspects of the marking device 110 according to one embodiment.
For example, the marking device 110 may include an elongated housing 136
in which is disposed one or more elements of the actuation system 120,
one or more elements of the control electronics 112 and the power source
114. Elongated housing 136 may be hollow or may contain certain cavities
or molded compartments for installing any components therein, such as the
various components of marking device 110 that are shown in FIG. 2. The
elongated housing 136 and other structural elements associated with the
housing, as discussed below, may be formed of any rigid, semi-rigid,
strong, and lightweight material, such as, but not limited to, molded
plastic and aluminum.

[0171]Incorporated at a proximal end of elongated housing 136 may be a
handle 138, which provides a convenient grip by which the user (e.g., the
locate technician) may carry the marking device 110 during use (i.e., the
exemplary marking device depicted in FIG. 3 is intended to be a hand-held
device). In one implementation, the power source 114 may be provided in
the form of a removable battery pack housing one or more rechargeable
batteries that are connected in series or parallel in order to provide a
DC voltage to marking device 110, and disposed within a compartment in
the handle 138. Such an arrangement facilitates use of conventional
removable/rechargeable battery packs often employed in a variety of
cordless power tools, in which the battery pack similarly is situated in
a handle of the tool. It should be appreciated, however, that the power
source 114 in the form of a battery pack may be disposed in any of a
variety of locations within or coupled to the elongated housing 136.

[0172]As also shown in FIG. 3, mounted near handle 138 is user interface
126, which may include a display 146. The display 146 may be a touch
screen display to facilitate interaction with a user/technician, and/or
the user interface also may include one or more buttons, switches,
joysticks, a keyboard, and the like to facilitate entry of information by
a user/technician. One or more elements of the control electronics 112
(e.g., the processor 118, memory 122, communication interface 124, and
timing system 128) also may be located in the proximal end of the
elongated housing in the vicinity of the user interface 126 and display
146. As with the power source 114, it should be appreciated that one or
more elements of the control electronics 112 may be disposed in any of a
variety of locations within or coupled to the elongated housing 136.

[0173]In the embodiment of FIG. 3, the location tracking system 130
similarly may be positioned on the proximal end of the elongated housing
136 to facilitate substantially unobstructed exposure to the atmosphere;
in particular, as illustrated in FIG. 3, the location tracking system 130
may be situated on an a ground plane 133 (providing an electrical ground
at least at the antenna frequency of the location tracking system, e.g.,
at approximately 1.5 GHz) that extends from the proximal end of the
housing 136 and is approximately parallel to the ground, surface or
pavement when the marking device is being normally operated by a
technician (so as to reduce signal modulation with subtle movements of
the marking device).

[0174]As also shown in FIG. 3, incorporated at the distal end of elongated
housing 136 is a marking dispenser holder 140 for holding one or more
marking dispensers 116 (e.g., an aerosol paint canister). Dispenser 116
may be one or more replaceable dispensers or one or more reusable
refillable dispensers (including a fixed reservoir forming a part of the
device 110) or any other suitable dispenser. Also situated at the distal
end of the housing is the marking material detection mechanism 132 to
detect a presence or absence of the marking dispenser 116 in the marking
material holder 140, and/or one or more characteristics of the marking
material 148, as well as an actuation mechanism 158, which in some
implementations may constitute part of the actuation system 120 and be
employed to interact with the marking dispenser 116 so as to effect
dispensing of the marking material 148.

[0175]With respect to the actuation system 120, as shown in FIG. 3, at
least a portion of the actuation system 120 is indicated generally along
the length of the elongated housing for purposes of illustration. More
specifically, however, in various implementations the actuation system
120 may include multiple components disposed in various places in, on or
coupled to the marking device 110. For example, in the embodiment of FIG.
3, the actuation system 120 includes an actuator 142, which for example
may be a mechanical mechanism provided at the handle 138 in the form of a
trigger that is pulled by a finger or hand of an user/technician. The
actuation system 120 further includes the actuation mechanism 158
disposed at the distal end of the marking device that is responsive to
the actuator 142 to dispense marking material. In general, in various
exemplary implementations as discussed in further detail below, the
actuation system 120 may employ any of a variety of mechanical and/or
electrical techniques to cause the marking dispenser 116 to dispense
marking material 148 in response to one or more signals or stimuli. In
the embodiment shown in FIG. 3, the signal/stimulus is initially provided
to the actuation system via the mechanical actuator 142; i.e., a locate
technician or other user triggers (e.g., pulls/depresses) the actuator
142 to provide a signal/stimulus to the actuation system 120, which in
turn operates the actuation mechanism 158 to dispense marking material in
response to the signal/stimulus.

[0176]In response to the signal/stimulus provided by the actuator 142, as
discussed above the actuation system may also provide an actuation signal
121 to the processor 118 to indicate an actuation. As discussed in
further detail below in connection with FIG. 9, pursuant to the execution
by the processor 118 of the marking data algorithm 134, the actuation
signal 121 may be used to cause the logging of information that is
provided by one or more components of the marking device 110 so as to
generate an electronic record of the marking operation.

[0177]FIGS. 4A and 4B illustrate a portion of the actuation system 120
according to one embodiment of the present invention. FIG. 4A shows the
actuator 142 in an un-actuated state, whereas FIG. 4B shows the actuator
142 in an actuated state (in which a signal/stimulus is provided by the
actuator). In the example of FIGS. 4A and 4B, the actuator 142 is coupled
to a mechanical coupler 152, similar to that shown in FIGS. 1A and 1B,
which extends along a length of the elongated housing and is in turn
coupled to a mechanical actuation mechanism 158 at the distal end of the
housing (not shown in FIGS. 4A and 4B) that ultimately effects dispensing
of marking material when the actuator is in the actuated state. The
portion of the actuation system 120 shown in FIGS. 4A and 4B also
includes a sensor 160 which is configured to provide an actuation signal
121 to the processor 118 to indicate one or both of the respective
actuated and un-actuated states of the actuator 142.

[0178]In one implementation, the sensor 160 may include a switch device
(e.g., a make/break single pole/single throw contact switch) disposed
along the handle 138 of the marking device such that, when pulled, the
actuator contacts (e.g., depresses) the switch causing a state of the
switch to toggle. In another implementation, the sensor 160 may include a
switch device such as a reed (magnetic) switch disposed at some point
along the length of the elongated housing; in such an implementation, the
mechanical coupler 152 may have a magnet disposed along it at an
appropriate position relative to the reed switch, such that movement of
the mechanical coupler 152 upon actuation of the actuator 142 causes a
state of the reed switch to toggle. Electrically, a switch device serving
as the sensor 160 may be coupled to ground or a DC supply voltage, such
that when the switch device is in a first state (e.g., closed/making
contact) the ground or DC supply voltage is passed to the processor 118
(e.g., via an I/O pin of the processor which provides an interrupt to, or
is periodically monitored by, the processor), and when the switch is in a
second state (e.g., open/no contact) the ground or DC supply voltage is
not passed to the processor 118. In this manner, the sensor 160 may
provide the actuation signal 121 to the processor indicating actuation
(and release) of the actuator 142.

[0179]FIG. 5 illustrates various components of an actuation system 120
according to other embodiments of the present invention. Generally
speaking, the actuation system 120 may include the actuator 142 and the
sensor 160 to detect actuation and release of the actuator 142 (and also
provide a corresponding actuation signal 121 representing same to the
processor 118). While a "trigger-pull" type of actuator 142 is shown
primarily for purposes of illustration in FIG. 5, it should be
appreciated that more generally an actuator of the actuation system 120
may be implemented by any form or combination of a lever, switch,
program, processor, screen, microphone for capturing audible commands,
and the like, as discussed above. For example, in one implementation, a
microphone may serve as both the actuator 142 and the sensor 160 shown in
FIG. 5 to provide an actuation signal 121 based on audible commands, so
as to effect voice-activated actuation of the marking device.

[0180]FIG. 5 also shows that the actuation system 120 of this embodiment
includes a link transmitter 168 coupled and responsive to the sensor 160
to transmit one or more signals and/or other stimulus via an actuation
link 164, and a link receiver 162 to receive the one or more signals
and/or other stimulus from the actuation link 164. In response to such
signals and/or other stimulus, the link receiver 162 operates the
actuation mechanism 158. The link transmitter 168, the link 164, and the
link receiver 162 may include one or more electrical and/or mechanical
components. For example, the link receiver 162 may include a linear
solenoid mechanically coupled to the actuation mechanism 158 and whose
movement is responsive to one or more signals and/or stimuli received
from the link 164. In various exemplary implementations, the link
transmitter 168 and the link 164 simply may include a wire that couples
the sensor 160 to the solenoid to activate the solenoid upon changes of
state in the actuation signal 121. Alternatively, the transmitter 168 may
be an RF transmitter that is activated in response to the actuation
signal 121, the link 164 may be a wireless link, and the receiver 162 may
include an RF receiver.

[0181]Other examples of transmitter/link/receiver combinations include,
but are not limited to, an acoustic transmitter/link/receiver (e.g., a
sound wave source that provides a sound wave of a certain tone, duration,
and/or amplitude when the actuator is actuated, and a corresponding sound
wave detector), an optical transmitter/link/receiver (e.g., a light or
laser source that provides an optical signal of a certain wavelength,
duration, and/or amplitude when the actuator is actuated, and a
corresponding optical detector), a fluid transmitter/link/receiver (e.g.,
a fluid system that provides a fluid control output of a certain volume,
pressure, and/or duration when the actuator is actuated, and a
corresponding fluid sensor for sensing the presence of, for example, a
short blast of water of a certain volume, pressure, and/or duration to
indicate an actuation; the fluid system may be, for example, a
closed-loop system that has a source reservoir at the top of the marking
device, a fluid line in proximity with the fluid sensor, a return
reservoir for capturing water during the actuation process, and
appropriate pressure regulation and ducts for cycling water from the
return reservoir back to the source reservoir), and an air
transmitter/link/receiver (e.g., an air system that provides an air
control output of a certain volume, pressure, and/or duration when the
actuator is actuated, and a corresponding air sensor for sensing the
presence of, for example, a blast or puff of air of a certain volume,
pressure, and/or duration to indicate an actuation).

[0182]While not explicitly shown in FIG. 5, in yet other embodiments it
should be appreciated that the sensor 160 may be coupled to the processor
118 (to provide the actuation signal 121 representing actuation/release
of the actuator), and in turn the processor may provide a signal to the
link transmitter 168, such that dispensing of marking material may in
part be under the control of the processor 118 executing particular
instructions for this purpose. More specifically, while in some
implementations dispensing of marking material may be directly responsive
to actuation of the actuator (and cease upon release of the actuator), in
other implementations dispensing of marking material may be initiated in
some manner upon actuation of the actuator, but then continued dispensing
of marking material may not necessarily be dictated by continued
actuation, or release, of the actuator. Rather, the processor 118 may
provide one or more signals or commands to the link transmitter 168 to
govern dispensing of marking material in some manner that does not
necessarily track each actuation and release of the actuator.

[0183]For example, in one implementation the processor 118 may execute
instructions such that, once the actuation signal 121 from the sensor 160
indicates actuation of the actuator, the processor 118 provides a signal
to the link transmitter 168 that causes dispensing of marking material
for some predetermined or user-defined amount of time, irrespective of
release of the actuator. Additionally or alternatively, the processor may
provide one or more signals to the link transmitter 168 that causes
dispensing of marking material for multiple discrete amounts of time with
a single actuation (e.g., three bursts of 1 second each per actuation).
From the foregoing, it should be generally appreciated that a wide
variety of marker sizes and patterns may be generated from the marking
device in an automated or semi-automated manner based on processor-based
control of the actuation system 120. It should also be appreciated that
automated or semi-automated processor-based control of the dispensing of
marking material may also govern in some fashion how, how often, and/or
what type of marking information is collected and logged to generate an
electronic record of a marking operation, as discussed further below in
connection with FIG. 9.

III. EXEMPLARY MARKING TECHNIQUES

[0184]FIGS. 6 and 7 provide examples of how the marking device 110 shown
in FIGS. 2 and 3 may be employed by a technician during a marking
operation. Referring now to FIG. 6, a perspective view of marking device
110 when in use for marking a "dotting pattern" is presented. In marking
operations, a dotting pattern may be utilized to preliminarily and
quickly indicate the presence or absence of a target facility during an
initial locate of a target facility. By way of example, FIG. 6 shows an
underground facility 310, which may be any facility, such as an
underground gas line, water pipe, sewer pipe, power line, telephone line,
cable television conduit, and the like. FIG. 6 also shows a dotting
pattern 312 that is formed by multiple locate marks 314 dispensed via
marking device 110. The locate marks 314 of dotting pattern 312 are
formed by successive short bursts of marking material (e.g., brief
actuations); i.e., each locate mark 314 corresponds to one brief
actuation of the marking device 110.

[0185]Referring now to FIG. 7, a perspective view of marking device 110
when in use for marking a "lines pattern" is presented. In marking
operations, a lines pattern is typically the end product of a marking
operation. This pattern extends the dotting pattern (e.g., dotting
pattern 312 of FIG. 6) so as to create lines (e.g., a series of dashes)
that indicate the presence or absence of an underground facility. These
lines subsequently provide important reference marks to an excavator so
as to avoid damage to a facility during excavation activities or other
disturbances of the ground. By way of example, FIG. 7 shows underground
facility 310, which may be any concealed facility, such as an underground
gas line, water pipe, sewer pipe, power line, telephone line, cable
television conduit, and the like. FIG. 7 also shows a lines pattern 412
that is formed by multiple locate marks 414 dispensed via marking device
110. A characteristic of locate marks 414 of lines pattern 412 is that
each locate mark 414 is formed by an extended burst of marking material
(e.g., a longer actuation of the marking device) as compared with a
dotting pattern. As with the dotting pattern shown in FIG. 6, however,
each locate mark 414 of the lines pattern shown in FIG. 7 may correspond
to one actuation of marking device 110. In some alternative
implementations, as discussed above, a series of locate marks (e.g., all
three marks 414) may be automatically generated by one actuation of
marking device 110 pursuant to processor-based control of the actuation
system.

[0186]FIG. 8 illustrates a plan view that shows further details of the
lines pattern 412 of FIG. 7. In the example of FIG. 8, each locate mark
414-1, 414-2, and 414-3 corresponds to one actuation ("act") of marking
device 110, i.e., locate mark 414-1 corresponds to act-1, locate mark
414-2 corresponds to act-2, and locate mark 414-3 corresponds to act-3.
Furthermore, each actuation and its corresponding locate mark 412 has a
start time t1, an end time t2, and a duration (Δt). While FIG. 8
shows three locate marks, it should be appreciated that lines pattern 412
may be formed by any number of locate marks.

[0187]In one embodiment of the present invention for generating an
electronic record of a marking operation, the processor 118 of the
marking device 110, executing the marking data algorithm 134, may collect
various marking information and generate an electronic record having one
or more "actuation data sets" respectively associated with one or more
actuations (act-1, act-2, act-3 . . . act-n) and corresponding locate
marks, as shown in FIG. 8. Marking information may be collected and
entered into such an electronic record at various times relative to the
start time t1 and the end time t2 of a given actuation, e.g., at t1 only,
at t2 only, at both t1 and t2, at any time(s) between t1 and t2, and/or
before or after t1 and t2.

[0188]Examples of marking information that generally (but not necessarily)
is acquired with respect to t1 and t2 of each actuation, and points
between t1 and t2 ("actuation data"), may include, but are not limited
to: [0189](1) timing information: time and date for one or both of t1
and t2 (hereinafter also referred to as "time stamp data"), and/or
duration (Δt) of the actuation, which may be provided in some
instances by timing system 128; and [0190](2) geographic information:
latitude and longitude data from location tracking system 130
(hereinafter also referred to as "geo-location data") (e.g., GPS data may
be expressed in degrees, minutes, and seconds (i.e., DDD°, MM',
and SS.S''), degrees and decimal minutes (DDD° and MM.MMM'), or
decimal degrees (DDD.DDDDD°)).

[0191]Examples of marking information that may be acquired before, during
or after a given actuation or succession of actuations, and also entered
into an electronic record, include, but are not limited to: [0192](3)
marking material information, such as the presence, color, brand and/or
type of dispensed marking material or a simulated dispensing of such
marking material (i.e., hereinafter also referred to as "product data");
[0193](4) service-related information: identification (ID) number of the
locate service provider (e.g., a party/company who dispatches the locate
technician, hereinafter also referred to as "service provider ID"); ID
number of the user and/or technician (hereinafter also referred to as
"user ID"); ID number of the marking device being used for the marking
operation (hereinafter also referred to as "device ID"); and [0194](5)
ticket information, such as the requesting party (e.g., excavator
information), type of facility requested to be marked by the requesting
party, and address of the work site/dig area for the marking operation
(hereinafter also referred to as "locate request data"). Ticket
information also may include a variety of text-based information which
may be included in an original locate request ticket, and/or text-based
or other information entered in by a technician (e.g., via the user
interface 126 and/or display 146) upon initiation of and/or during a
marking operation, such as ground type information (e.g., a description
of the ground at which marking material is dispensed). Thus, ticket
information may be received or derived from a locate request ticket
and/or provided by another source, such as entry by a user/technician.

[0195]In exemplary methods for generating an electronic record of marking
operations according to some embodiments of the invention, as discussed
in greater detail below, for a given actuation the processor 118 may
request the location tracking system 130 to provide geographic
information at one or more times during the actuation (e.g., periodically
at regular intervals). Thus, an actuation data set of an electronic
record for a given actuation of the marking device may have multiple
pieces of geographic information (and associated time stamps)
representing the location of the marking device at multiple times during
a corresponding actuation. Additionally, for a given actuation, the
processor 118 also may request the marking material detection mechanism
132 to provide marking material information as part of the actuation data
set. The processor also may include ticket information and
service-related information, which may be collected (e.g., via one or
more of the user interface 126 and the communication interface 124)
before a corresponding actuation, stored in memory 122 and retrieved from
the memory for entry into the electronic record upon or during the
corresponding actuation, or collected and entered into the electronic
record upon or during the corresponding actuation.

[0196]While the collection and logging of marking information to generate
an electronic record is discussed in some aspects, for purposes of
illustration, in terms of actuation data sets (i.e., a set of data that
is associated and logged with a corresponding actuation of the marking
device), it should be appreciated that various embodiments of the present
invention are not limited in this respect. More generally, an electronic
record of a marking operation may be generated in any of a variety of
manners, have a variety of file formats and/or data structures, and
include any of a variety of marking information (some of which may be
germane to one or more actuations of the marking device and some of which
may be common to multiple actuations or the overall marking operation in
general).

[0197]FIG. 9 is a flow diagram of an exemplary process 600 for collecting
marking information during operation of a marking device 110 and
generating an electronic record, according to one embodiment of the
present invention. It should be appreciated that as various marking
information is collected and logged in the process 600, such marking
information also may be transmitted from the marking device (e.g., to
remote computer 150) to facilitate essentially real-time monitoring of
the marking operation, and/or remote generation of an electronic record
of the marking operation.

[0198]In block 602 of the process 600 shown in FIG. 9, ticket information
and/or service-related information may be received (e.g., via one or more
of the user interface 126 and the communication interface 124 of marking
device 110) and this information optionally may be stored in whole or in
part in local memory 122 of the marking device. The ticket information
and/or service-related information may be received electronically in any
of a variety of formats, and the processor may be configured to
appropriately parse the information for subsequent entry into an
electronic record.

[0199]For example, in some embodiments, the ticket information may be
received as part of an electronic locate request ticket, and individual
respective pieces of ticket information (e.g., ticket number, work site
address information, requesting party, etc.) may be extracted or derived
from the electronic locate request ticket. In other embodiments, various
aspects of ticket information may be input by a user/technician via the
user interface.

[0200]For example, in block 602 the process 600 may provide for the entry
of any of a variety of text information for inclusion in an electronic
record and/or selection by a user/technician (e.g., via the user
interface) of various information to be included in an electronic record
as part of ticket information (and/or service-related information). One
example of such information may relate to a ground type in and around the
work site/dig area at which marking material is dispensed as part of the
marking operation. In some implementations, a text description of the
ground type may be entered and stored as part of the electronic record.
In another exemplary implementation, the processor 118 controls the user
interface 126 (including display 146) so as to display information to the
technician to facilitate such a selection. In particular, a ground type
selection submenu may be displayed, including one or more categories of
ground types displayed in any of a variety of manners (e.g., as a list of
text entries, an arrangement of icons symbolizing respective categories,
labeled symbols, etc.). Examples of ground type categories that may be
displayed in such a submenu include, but are not limited to: 1)
"Pavement;" 2) "Grass;" 3) "Rough/Rocky;" 4) "Dirt;" 5) "Gravel/Sand;"
and 6) "Other." More generally, any number and variety of ground type
categories may be presented to the technician via the user interface in
alphabetically ordered lists, numerically ordered lists, or other types
of ordered text-based or symbolic arrangements, for example. In yet
another exemplary implementation, the user interface may include a
microphone and the processor may be configured to accept and process
audible commands, such that a ground type category may be accomplished
via voice-activated commands by simply speaking into the microphone.

[0201]Similarly, with respect to service-related information, a
user/technician may manually enter some aspects of this information via
the user interface/display, while other aspects may already be available
in other memory locations (e.g., the marking device ID or serial number,
a technician ID to which the marking device is assigned or checked-out,
etc.) and/or may be received electronically.

[0202]While block 602 is illustrated as one element of the process 600, it
should be appreciated that respective pieces of information received as
input in block 602 may be received at different times and via different
interfaces/sources, and thus may occur at different points in the process
600. It should also be appreciated that block 602 is an optional step in
the process 600, and that more generally a process for collecting marking
information to generate an electronic record need not necessarily include
collection of one or both of ticket information and service-related
information.

[0203]In block 604, the locate technician utilizes the user interface 126
to indicate the initiation of a marking operation. For example, the
technician may press a button, operate a joy-stick, or touch a touch
screen display portion of a graphical user interface to commence a
marking operation. In response, a "job initiation signal" is provided to
the processor 118 (e.g., via a switch closure and a ground or DC level
applied to an I/O pin of the processor, or by the user interface
providing a signal to the processor) to initiate generation of an
electronic record. Alternatively, a remote job initiation signal may be
received by the processor via the communication interface from another
device, such as the remote computer 150.

[0204]In response to the job initiation signal, in block 606 the processor
opens a file in the memory 122 in which to store the electronic record
135, and assigns a file identifier to the opened file. In one example,
the file identifier assigned to the opened file may be or include one or
more of a job number ("job ID") or ticket number derived from the ticket
information and/or the service-related information, an identifier for the
marking device itself, and an identifier for a remote computer associated
with the marking device (e.g., for either remote control operation of the
device and/or data uploading/downloading). To this end, if ticket
information and/or service-related information is not previously
available (e.g., if no information is received in block 602), the
technician optionally may be prompted to manually enter (e.g., via a
"wizard" or sequence of dialogues germane to obtaining relevant
information displayed on the display of the user interface) various
elements of ticket information and/or service-related information from
which a file identifier may be derived, or provide other information that
may be used as a file identifier.

[0205]A file opened in block 606 for purposes of storing an electronic
record may have any of a variety of formats and include any of a variety
of data structures. In one embodiment, the processor initially opens up a
"flat file" for collection and logging of marking information to
facilitate generation of an electronic record. As known in the art, a
flat file is a plain text or mixed text/binary file containing one entry
(data record) per line, in which each entry may have multiple fields
containing respective values, and wherein the respective values may be
separated by delimiters (e.g., commas) or have a fixed length. In one
exemplary implementation, the processor 118 logs data into a flat file
opened for the electronic record as a succession of time stamped "event
entries." Some event entries may be related specifically to actuation
and/or logged in response to actuation of the marking device (e.g., the
processor 118 receiving an actuation signal 121). Other event entries may
be more generally related in some manner to overall operation of the
marking device or the marking operation itself, but not necessarily
associated with one or more particular actuations (e.g., start/pause/stop
marking operation, power/battery status, communication link/network
connection status, etc.), and these other event entries may be logged at
virtually any time (in some cases irrespective of one or more
actuations).

[0206]Accordingly, it should be appreciated that in one aspect of this
embodiment a flat file for an electronic record may contain a succession
of time stamped event entries on respective lines, in which one or more
event entries may have multiple delimited fields/values and at least some
of the event entries relate to actuation of the marking device. In
another aspect, one or more fields/values in a given event entry may
specifically indicate in some manner whether or not the event is
associated with an actuation of the marking device. In general, an
"actuation event entry" constitutes an entry in a file for an electronic
record that is in some manner specifically related to, and/or logged in
response to or during, actuation of the marking device, and multiple
actuation event entries for a given actuation constitute an actuation
data set for that actuation. Again, it should be appreciated that a file
for an electronic record may include one or more other event entries that
may not be particularly associated with an actuation.

[0207]In other embodiments, the file for an electronic record may or may
not be a flat file, and event entries associated with actuations
(actuation event entries) may be somehow identified and differentiated
from other event entries that are not associated with an actuation. For
example, a file for an electronic record may include a particular data
structure or format that segregates or separates in some manner event
entries associated with successive actuations from those event entries
that are not particularly associated with actuations (and/or may be
common to multiple actuations or a group of actuations). In yet other
embodiments, as discussed below, marking information may be initially
collected and logged in a first file for an electronic record in a first
format (e.g., a flat file including a succession of time-stamped event
entries as "raw data" for the marking operation) that may be stored
and/or transmitted for any of a variety of purposes, and then reformatted
and/or reorganized in some manner in one or more subsequent files (e.g.,
a file having a particular data structure that segregates/separates
actuation-related information from other information in different
fields/elements of a data structure) for archiving and/or transmission to
one or more other devices/processors.

[0208]Once a file for an electronic record is opened in block 606, in
block 608 the processor can begin collecting and logging various marking
information, i.e., logging in the electronic record (and/or transmitting
via the communication interface) actuation event entries and/or other
event entries. In one exemplary implementation, the processor may be
programmed so as to poll one or more input devices and/or other
components of the marking device to receive information, either once or
multiple times/periodically following the job initiation signal, and log
responses to these polls ("polling events") as event entries with
associated time stamps. Examples of entries corresponding to polling
events that may be logged into the file for the electronic record (and/or
transmitted) include, but are not limited to, one or more "power status
event entries" including power information associated with the power
source 114, one or more "ticket information event entries" including
ticket information (e.g., as received from the user interface or the
communication interface, retrieved from local memory, etc.), one or more
"service-related information event entries" including the service-related
information (e.g., as received from the user interface or the
communication interface, retrieved from local memory, etc.), and one or
more "communication interface event entries" including status information
regarding operation of the communication interface (e.g., network
communication available/unavailable).

[0209]Additionally or alternatively, the processor may be programmed so as
to respond to one or more signals designated as "interrupt events" from
one or more components of the marking device. Such interrupt events cause
logging of information in the electronic record (and/or transmission of
information) upon/following the processor detecting the corresponding
signal(s). For example, the "job initiation signal" itself may constitute
an interrupt event, in response to which the processor 118 not only opens
a file for the electronic record but, once the file is opened, the
processor may request timing information from the timing system 128 and
log into the electronic record a "start job event entry" including a job
initiation time stamp associated with receipt of the job initiation
signal.

[0210]In a similar manner, following commencement of a marking operation,
the locate technician may utilize the user interface 126 (e.g., press a
button, operate a joy-stick, or touch a touch screen display portion of a
graphical user interface) to pause, restart, and/or indicate completion
of the marking operation, and these actions may constitute interrupt
events. For example, as indicated in block 610 of FIG. 9, a "pause
signal" may be provided by the user interface to the processor, in
response to which the processor may request timing information from the
timing system and log a "pause job event entry" including a pause job
time stamp associated with the at least one pause signal. When the
technician is ready to continue, as shown in block 612 of FIG. 9 the
technician may indicate this via the user interface and a "restart job
event entry" similarly may be logged. When the marking operation is
deemed by the technician to be completed, as noted in block 614 of FIG. 9
the technician may utilize the user interface so as to provide a "stop
signal" to the processor, in response to which the processor may request
timing information from the timing system and log a "stop job event
entry" including a stop job time stamp associated with the stop signal.

[0211]Additionally, the locate technician may utilize the user interface
126 to denote the beginning and end of a marking operation for a
particular facility type, and these actions may constitute interrupt
events. For example, upon beginning a marking operation for a given
facility type, the technician may select "line start" from the user
interface, and a corresponding "line start signal" may be provided by the
user interface to the processor, in response to which the processor may
request timing information from the timing system and log a "line start
event entry." Similarly, when the technician wishes to indicate
completion of the marking operation for a given facility type, the
technician may select "line stop" from the user interface, and a
corresponding "line stop signal" may be provided by the user interface to
the processor, in response to which the processor may request timing
information from the timing system and log a "line stop even entry."

[0212]While various events are noted above as examples of "polling events"
as opposed to "interrupt events," it should be appreciated that the
invention is not limited in these respects, and that the marking data
algorithm 134 executed by the processor 118 may be configured in any of a
variety manners to designate various functions performed by and/or
information provided by various components of the marking device as
polling events or interrupt events. For example, the power source 114 may
be configured to provide a "low battery signal" to the processor, which
when present is treated by the processor as an interrupt event that may
be logged by the processor and/or that may cause the processor to take
some particular action (e.g., provide an audible/visible alert; disable
logging of further data, etc.). In one aspect, absent the "low battery
signal," the processor may request status information from the power
source once or occasionally as a polling event. Similarly, the
communication interface 124 may be configured to provide a "no network
connection available signal" to the processor, which when present is
treated by the processor as an interrupt event (that is logged and/or
causes the processor to take some action), and when not present, the
processor may poll the communication interface to request status
information as a polling event.

[0213]Another example of an interrupt event is given by the actuation
signal 121 provided by the actuation system 120 upon actuation of the
actuator 142 (i.e., a signal change-of-state indicating a transition from
a non-actuated state to an actuated state), in response to which the
processor logs one or more actuation event entries in the electronic
record. More specifically, in one implementation, the receipt of a
non-actuated to actuated transition state of the actuation signal 121 by
the processor may cause an initial actuation event entry to be logged as
a "start actuation event entry" having an associated time stamp (i.e., a
start time for the corresponding actuation) and also cause the processor
to subsequently poll one or more input devices for information during the
corresponding actuation and until release of the actuator (i.e.,
subsequent change of state of the actuation signal 121). In this manner,
an actuation data set for a given actuation may include multiple
actuation event entries.

[0214]For example, during actuation of the actuator, the processor may
poll the location tracking system 130 so as to receive geographic
information, and in turn log one or more "geo-location data event
entries" in the actuation data set for the corresponding actuation. As
discussed above in connection with FIGS. 2 and 3, in one exemplary
implementation the location tracking system is configured to provide
geographic information at an information update rate of approximately 5
Hz, and the processor may log respective updates of geographic
information provided by the location tracking system at this update rate
during an actuation as multiple geo-location data event entries of the
actuation data set. It should be appreciated, however, that methods and
apparatus according to various embodiments of the present invention are
not limited in this respect, and that other geographic information update
rates may be employed in various implementations (e.g., update rates of
up to approximately 100 Hz), based in part on the particular location
tracking system employed. Furthermore, it should be appreciated that in
some implementations the geographic information provided by the location
tracking system 130 may include one or more longitude coordinates,
latitude coordinates, and a corresponding geo-location data time stamp at
which a given set of longitude/latitude coordinates are obtained by the
location tracking system; accordingly, a given geo-location data event
entry in an actuation data set may include a longitude coordinate, a
latitude coordinate, and the corresponding geo-location data time stamp.

[0215]Similarly, in some implementations, pursuant to an interrupt
provided by the actuation signal 121, the processor may subsequently poll
one or more of the timing system 128 and the marking material detection
mechanism 132 so as to receive timing information and/or marking material
information during a corresponding actuation, and in turn log one or more
of a "timing event entry," and a "marking material detection event entry"
as part of the actuation data set. Any of a variety of marking material
information as discussed above may be collected and logged during
actuation in response to processor polling of the marking material
detection mechanism (e.g., causing an RFID tag reader to read various
information from an RFID tag affixed to the marking dispenser).

[0216]Additionally, in some implementations, pursuant to an interrupt
provided by the actuation signal 121, the processor may subsequently poll
one or more of the user interface 126, the communication interface 124,
and the local memory 122 to retrieve ticket information and/or
service-related information for logging into an actuation data set. As
discussed above, in some implementations the receipt/retrieval of ticket
information and/or service-related information may be treated as a
polling event not necessarily associated with actuations, and this
information need not be included in one or more actuation data sets.
However, in other implementations it may be desirable to include at least
some aspect of ticket information and/or service related information in
each actuation data set, notwithstanding the possible redundancy of data
content in respective actuation data sets (e.g., see Table 6, discussed
further below in connection with FIG. 10).

[0217]Another example of an interrupt event is given by a change-of-state
of the actuation signal 121 indicating a transition from the actuated
state to the non-actuated state, i.e., release of the actuator 142. In
response to this event, the processor may request information from the
timing system 128 and log an "end actuation event entry" including an end
time stamp.

[0218]Yet another type of interrupt event causing the processor to log one
or more event entries may be provided by the marking material detection
mechanism 132 in the form of a signal that indicates whether or not a
marking dispenser is contained in or appropriately coupled to the marking
device. To this end, as discussed above in connection with FIGS. 2 and 3,
the marking material detection mechanism may include a toggle switch that
provides a two-state signal to the processor (e.g., dispenser
in/dispenser out) as an interrupt. Upon receiving an interrupt indicating
a transition from "dispenser out" to "dispenser in," the processor may
collect and log this event as a "dispenser in event entry" with a
corresponding time stamp, and then request other marking material
information relating to the marking material in the dispenser from the
marking material detection mechanism. In view of the foregoing, it should
be appreciated that in some embodiments, marking material information may
not necessarily be collected during one or more actuations of the marking
device, but alternatively may be collected only upon a "dispenser in"
event being detected. Upon detection of an interrupt event indicating a
transition from "dispenser in" to "dispenser out," the processor
similarly may collect and log this event as a "dispenser out event
entry."

[0219]In yet another embodiment, the processor 118, executing marking data
algorithm 134, may be configured to repeatedly/regularly poll all
available input devices and other components of the marking device (e.g.,
in a predetermined order, in response to receipt of the job initiation
signal) and generate an essentially continuous stream of data packets
including marking information received pursuant to these polling events.
In one aspect of this embodiment, each data packet of marking information
may include a header, one or more flag fields, and one or more
information payload fields. For example, in one implementation, the
header for each packet may include one or more of a job ID (e.g., ticket
identifier), technician ID, device ID (e.g., serial number), packet type
ID, and/or a time stamp corresponding to logging of
information/generation of the packet. Each packet also may include one or
more payload fields for carrying information provided by the polled
device(s) or components, and one or more flag fields that are set (or
reset) upon occurrence of one or more predetermined interrupt events
(e.g., pull/depress actuator, release actuator, marking dispenser in,
marking dispenser out, low power, communication link fail, etc.). In this
manner, a continuous stream of data may be provided as an output by the
processor, in which certain interrupt events, such as an actuation and/or
release of the actuator, "tag" certain data packets via an interrupt
flag. In yet other aspects of this embodiment, all data packets thusly
generated may be stored in the file opened for the electronic record
and/or transmitted from the marking device in essentially real time;
alternatively, only certain data packets with one or more predetermined
flags set may be stored and/or transmitted.

[0220]Table 1 below illustrates an example of a portion of the contents of
a relatively simple flat file for an electronic record that may be
generated by the process 600 of FIG. 9:

The portion of the file shown in Table 1 corresponds to multiple actuation
event entries (one entry per line) collected and logged during an
actuation of the marking device. Each entry has a time stamp (e.g.,
entries are logged at a rate of approximately five events per second) and
further includes multiple fields having respective values (e.g., as comma
separated values) for latitude and longitude coordinates received from
the location tracking device, an event indicator indicating that the
device is "Spraying" (the actuator is actuated), and a color of the
marking material being dispensed.

[0221]As noted above, it should be appreciated that the portion of the
file shown in Table 1 is provided primarily for purposes of illustration,
and that the format and/or content for respective event entries and the
file itself for an electronic record generated by and/or based on the
information collection process discussed above in connection with FIG. 9
may have any of a variety of different formats and/or content.

[0222]To this point, Tables 2 through 5 below provide examples of various
events for which event entries may be logged in a file for an electronic
record and/or transmitted by the marking device, exemplary formats for
these event entries, and exemplary file formats for files having multiple
such entries, according to another embodiment of the present invention.

[0223]Job Started/Paused/Restarted/Completed Events: This event entry
format provides information about when a marking operation ("job") was
started and completed in addition to capturing details about if and when
the job was paused and restarted.

[0224]Actuation State Change Events: For purposes of this event format,
the actuator is deemed to have three possible states, i.e., PRESSED, HELD
and RELEASED. Marking information from one or more input devices/other
components of the marking device is recorded with these events to provide
information about the job in progress.

[0225]Marking Device Status Events: The status event collects various
marking information and/or information on operating characteristics of
the device on a periodic basis while a job is in progress (e.g., pursuant
to processor polls).

[0226]Error Events: Should any input device or other component of the
marking device encounter a significant error condition, this may be
logged as an event. In some cases, the user/technician also may be
notified of the error through the user interface 126 (visible alert on
display, audible alarm/alert, etc.). Similar event formats may be adopted
for warning alerts/events and informational alerts/events.

[0227]With respect to file formats for electronic records including the
event entries outlined above in Tables 2 through 5, two exemplary file
formats, namely ASCII and XML, are provided below for purposes of
illustration. In various implementations, a given marking device may be
particularly configured to store and/or transmit electronic records and
respective entries therein in either format (or other formats). With
respect to identification of files/electronic records, a standard naming
scheme/format may be adopted, for example, including an identifier for
the remote computer with which the marking device may be communicating
("ServerID"), an identifier for the marking device itself ("WandID"), and
an identifier for the marking operation/job ("JobID"), and having the
format "ServerID_WandID_Job ID."

[0228]ASCII Data Format: This format allows low-level remote processing
engines to quickly and easily receive, parse, and react to marking
information logged and/or transmitted by the marking device. An example
of an electronic record formatted in ASCII based on the event entries
outlined in Tables 2 through 5 is as follows:

[0229]XML Data Format: This format allows transmission of self-describing
data elements from the marking device, in some instances reducing
processing errors and reducing the risks and effort involved in upgrades
and data changes. An example of an electronic record formatted in XML
based on the event entries outlined in Tables 2 through 5 is as follows:

[0230]Yet another alternative format for storing and organizing marking
information in an electronic record of a marking operation, according to
one embodiment of the invention, is shown in Table 6 below. By way of
example, Table 6 shows the format and content of three actuation data
sets of an electronic record of a marking operation for a given facility,
in which each actuation data set includes information associated with
multiple actuation event entries logged during a corresponding actuation
and resulting locate mark (e.g., act-1, act-2, and act-3), as shown for
example in FIG. 8. As discussed above, it should be appreciated that the
format and content shown below in Table 6 may constitute an "original"
electronic record generated by the processor pursuant to the process 600
shown in FIG. 9, or may be derived from raw data collected and logged
pursuant to the process 600 (e.g., as a flat file, an ASCII formatted
file, or an XML formatted file) and subsequently reorganized and
particularly formatted.

[0231]In addition to the information shown in Table 6, a job ID or some
other identifier for the electronic record as a whole (e.g., a ticket
number), as well as a total number of actuations for a given marking
operation (e.g., the total number of actuation data sets in a given
electronic record in this embodiment), may be included in the electronic
record.

[0232]With regard to color information that may be included in any of the
event entries and electronic records discussed herein, Table 7 below
shows an example of the correlation of marking material color to the type
of facility to be marked.

[0233]FIG. 10 illustrates an exemplary data structure for an electronic
record 135, according to another embodiment of the present invention,
that may be generated by and/or based on information collected during the
process 600 discussed above in connection with FIG. 9 and based on the
organization of information shown in Table 6 above. As shown in FIG. 10,
the record 135 includes a file identifier 701 (e.g., one or more of Job
ID, WandID, ServerID, etc.) and a plurality of actuation data sets 1
through N (with reference numbers 702A, 702B, 702C . . . 702N), wherein
each actuation data set is associated with a corresponding actuation of a
marking device. For purposes of the following discussion, FIG. 10 shows
additional details of the data structure for actuation data set 3 702C,
showing several fields in which data (e.g., actuation event entries) may
be entered to constitute the actuation data set. While only the exemplary
details of the data structure of actuation data set 3 are shown in the
electronic record 135 of FIG. 10, it should be appreciated that multiple
actuation data sets of the electronic record 135 may have the same data
structure as that shown for actuation data set 3 in FIG. 10.

[0234]The data structure of the actuation data set 3 702C of the
electronic record 135 shown in FIG. 10 includes a start location field
704 (corresponding to T1 geo-location data shown in Table 2), an end
location field 713 (corresponding to T2 geo-location data shown in Table
2), a start time field 706 (corresponding to T1 timestamp data shown in
Table 2), an end time field 708 (corresponding to T2 timestamp data shown
in Table 2) and a duration field 709 (corresponding to the duration
Δt shown in Table 2). Additionally, the data structure for entry 3
702C includes one or more fields 712A, 712B, . . . 712N for intermediate
location data (corresponding to 1st interval location data, 2nd
interval location data . . . Nth interval location data shown in Table
2). Finally, the data structure for the entry 3 702C may include one or
more ticket information fields 714 (e.g., corresponding to Locate request
data in Table 2) and one or more service-related information fields 716
(e.g., corresponding to Service provider ID, User ID, and Device ID in
Table 2).

[0235]In addition to one or more actuation data sets corresponding to
actuations of a marking device, the electronic record 135 shown in FIG.
10 may include one or more additional elements. For example, FIG. 10
shows an additional element 718 of the electronic record to store the
total number of entries in the record. Furthermore, according to another
embodiment, various other information that may be common to multiple (or
all) actuation data sets of a given electronic record may be stored in
one or more additional elements of the electronic record that are not
contained within one or more of the actuation data sets themselves. For
example, in one alternative implementation, one or more of the ticket
information field 714, the service-related information field 716, and the
marking material properties field 710, which are shown as part of the
data structure for a given actuation data set of the electronic record,
may instead be elements of the electronic record that are not included
within any one actuation data set (e.g., the information contained in one
or more of the ticket information field and the service-related
information field may be common to all actuation data sets of a given
electronic record).

V. LANDMARK IDENTIFICATION MODE

[0236]In yet another embodiment of the present invention, the marking
device 110 shown in FIGS. 2 and 3 may be configured (e.g., via particular
instructions included in the marking data algorithm 134 executing on the
processor 118, and/or various hardware modifications) to operate in
multiple different modes so as to collect various information relating
not only to a marking operation itself (marking information), but
additionally (or alternatively) various information relating to the work
site/dig area in which the marking operation is performed. For example,
in one implementation, the marking device may be configured to operate in
a first "marking mode" which essentially follows various aspects of the
process outlined in FIG. 9, and also operate in a second "landmark
identification mode" (or more simply "landmark mode"), in which the
marking device acquires information relating to one or more environmental
landmarks that may be germane to the marking operation (e.g., in and
around the work site/dig area and/or generally in the vicinity of the
marking operation).

[0237]More specifically, in a "marking mode," marking material may be
dispensed with respective actuations of the marking device and various
information transmitted and/or stored in an electronic record attendant
to this process, as discussed above. Alternatively, in a "landmark mode,"
marking material is not necessarily dispensed with an actuation of the
marking device (and in some instances the dispensing of marking material
is specifically precluded); instead, a technician positions the marking
device proximate to an environmental landmark of interest and, upon
actuation, the marking device collects various information about the
landmark (hereafter referred to as "landmark information"), which
information may include, but is not limited to, geo-location data of an
environmental landmark, type of environmental landmark, and a time stamp
for any acquired information relating to an environmental landmark.

[0238]FIGS. 11A and 11B are similar to FIGS. 4A and 4B, and conceptually
illustrate a portion of an actuation system 120 including a mechanical
coupler 152, in which the marking device 110 has been modified to include
a mode selector device so as to accommodate a landmark mode, according to
one embodiment of the present invention. In a manner similar to that
shown in FIGS. 4A and 4B, FIG. 11A shows the actuator 142 in an
un-actuated state, whereas FIG. 11B shows the actuator 142 in an actuated
state. In the embodiment of FIGS. 11A and 11B, the modifications are such
that, in the landmark mode, the marking device is precluded from
dispensing markers or marking material, even though the actuator 142 may
be actuated by a user.

[0239]More specifically, as shown in FIGS. 11A and 11B, in this embodiment
the marking device 110 further includes a mode selector device in the
form of a bypass device 145 that is operated so as to impact and deflect
the mechanical coupler 152 of the actuation system 120, such that the
mechanical coupler 152 fails to cause the dispensing of a marking
material upon actuation of the actuator 142. In FIG. 11A, the bypass
device is shown in a first state (e.g., released) which allows the
marking device to operate in marking mode as described above (i.e., the
mechanical coupler is allowed to be displaced essentially vertically with
actuation of the actuator 142 and thereby dispense markers). In FIG. 11B,
the bypass device is shown in a second state (e.g., depressed) which
allows the marking device to operate in landmark mode; in particular, the
mechanical coupler 152 is deflected by the bypass device such that upon
actuation of the actuator 142, the mechanical coupler 152 is not
displaced vertically. In one example, with reference again to FIGS. 1B
and 11B, when the mechanical coupler 152 is deflected by the bypass
device 145, actuations of the actuator 142 do not effect full essentially
up/down vertical movement of the mechanical coupler 152; as a result, the
mechanical coupler fails to displace the actuation mechanism, and no
pressure is applied to the spray nozzle of a paint dispenser (or
dispensing mechanism of other types of marker dispensers). At the same
time, however, actuation of the actuator 142 nonetheless provides an
actuation signal 121 to the processor 118 (which may provide for logging
of an actuation event entry as discussed above).

[0240]In various implementations, the bypass device 145 may be a locking
and/or spring-loaded switching device (e.g., a press/release locking
thumb switch) appropriately positioned along the housing of the marking
device (e.g., near or on the handle), wherein the bypass device provides
for both deflection of the mechanical coupler as well as opening/closure
of electrical contacts so as to provide a mode signal 147 to the
processor 118. For example, as shown in FIG. 11A, the first state
(released) of the bypass device 145 may include an open contact state and
no deflection of the mechanical coupler, whereas the second state shown
in FIG. 11B (depressed) may include a closed contact state (e.g., in
which the mode signal 147 is provided to the processor 118 as an
interrupt event to indicate "landmark mode") when the bypass device
deflects the mechanical coupler 152.

[0241]In response to the mode signal 147 indicating landmark mode, the
processor 118 may request timing information from the timing system and
log into an electronic record a "landmark mode event entry" including a
landmark mode time stamp associated with the landmark mode signal.
Additionally, or alternatively, the processor may respond to the landmark
mode signal by taking one or more other actions pursuant to execution of
a portion of the marking data algorithm 134 including particular
instructions to implement the landmark mode, such as providing for the
selection of landmark categories and/or types (via the user interface 126
and menus provided on the display 146), and logging actuation event
entries in an electronic record as "landmark event entries." Further
details of landmark mode operation of the marking device are discussed
below in connection with FIG. 12.

[0242]In another exemplary implementation, rather than employing the
bypass device 145 shown in FIGS. 11A and 11B as a mode selector device, a
marking device configured to implement a landmark mode in which no marker
or marking material is dispensed may be modified to include an actuator
locking device as a mode selector device to prevent operation of the
actuator 142. In essence, such a device would function in a manner
similar to a "trigger lock." Like the bypass device, the actuator locking
device or "trigger lock" may not only mechanically impede operation of
the actuator, but also include electrical switch contacts (opened/closed)
so as to provide a mode signal to the processor to indicate a landmark
mode when the actuator locking device is engaged to impede actuation.
Because such an actuator locking device impedes operation of the
actuator, the actuator itself cannot be employed to provide an actuation
signal 121 to the processor to facilitate the logging into an electronic
record of actuation event entries as "landmark event entries."
Accordingly, in implementations involving an actuator locking device,
another aspect of the user interface (e.g., a button, switch, portion of
the touch screen display, microphone to provide for voice-activation,
etc.) is employed to provide a signal to the processor 118 to facilitate
logging of an event (e.g., a "landmark event") by the technician. Further
details of logging of landmark events are discussed below in connection
with FIG. 12.

[0243]Yet another exemplary implementation of a marking device modified to
operate in landmark mode is based on the general implementation of an
actuation system 120 shown in FIG. 5, in which the landmark mode is
selected via the user interface 126 and/or display 146 (e.g., menu-driven
GUI) rather than via a bypass device or actuator locking device; i.e.,
some functionality of the user interface itself provides for a mode
selector device. With reference again to FIG. 5, dispensing of marking
material in this implementation is controlled by a link transmitter 168.
As discussed above in connection with FIG. 5, the link transmitter 168
may be responsive to the actuation signal 121 provided by sensor 160 with
operation of the actuator 142, for example, or alternatively responsive
to a signal provided by the processor 118 (such that dispensing of
marking material may in part be under the control of the processor 118
executing particular instructions for this purpose). Accordingly, in this
implementation, when a landmark mode is selected via the user interface
126, the marking device may be configured to either dispense marking
material (by not impeding any control signals to the link transmitter
168) (e.g., so as to form one or more "landmark locate marks" on or near
a target environmental landmark), or not to dispense marking material (by
impeding control signals to the link transmitter 168 or otherwise
controlling the link transmitter to not dispense marking material). In
either case, the actuation signal 121 output by sensor 160 may
nonetheless be provided to the processor 118 so as to facilitate logging
of an actuation event entry upon actuation of the actuator 142, which in
landmark mode may be designated as a "landmark event entry," as discussed
further below in connection with FIG. 12.

[0244]FIG. 12 is a flow diagram of an exemplary process 1200, according to
one embodiment of the present invention, for operating a marking device
having a marking mode and a landmark mode so as to collect marking
information and/or environmental landmark information during operation of
the marking device, and generate an electronic record of such
information. Several aspects of the process 1200 shown in FIG. 12 are
substantially similar or identical to those discussed above in connection
with FIG. 9; in particular, blocks 602 through 614 are the same in both
FIGS. 9 and 12, and the blocks 616, 618, and 620 in FIG. 12 are
additional aspects of the process 1200.

[0245]In the process 1200 outlined in FIG. 12, following commencement of a
marking operation the locate technician may utilize the user interface
126 (e.g., press a button, operate a joy-stick, touch a touch screen
display portion of a graphical user interface, speak into a microphone to
provide a voice-activated command, etc.) to not only pause, restart,
and/or indicate completion of the marking operation, but further to
select a landmark mode of operation for the marking device. As noted
above in the discussion of FIG. 9, any one or more of these actions may
constitute interrupt events. For example, as indicated in block 616 of
FIG. 12, if a technician selects "landmark mode" via the user interface,
the user interface may provide a "landmark mode signal" to the processor.
In response to this signal, the processor may request timing information
from the timing system and log a "landmark mode event entry" including a
landmark mode time stamp associated with the landmark mode signal.
Additionally, or alternatively, the processor may respond to the landmark
mode signal by taking one or more other actions pursuant to execution of
a portion of the marking data algorithm 134 including particular
instructions to implement the landmark mode (as discussed above, the
landmark mode may be entered in alternative implementations via a mode
signal provided to the processor 118 by a bypass device or an actuator
locking device serving as a mode selector device).

[0246]Table 8 below provides an example of content and format for a mode
select event entry that may be logged in a file for an electronic record
and/or transmitted by the marking device. The example mode select event
entry shown below in Table 8 follows a similar format to that used for
the event entry examples provided in Tables 2-5 above.

[0247]In the process outlined in FIG. 12, subsequent to selection of the
landmark mode, as noted in block 618 the process may provide for the
selection of a particular category and/or type of landmark for which
information is to be collected. To this end, in one implementation the
processor 118 controls the user interface 126 (including display 146) so
as to display information to the technician to facilitate such a
selection. In particular, a landmark selection submenu may be displayed,
including one or more categories of landmarks displayed in any of a
variety of manners (e.g., as a list of text entries, an arrangement of
icons symbolizing respective categories, labeled symbols, etc.). Examples
of landmark categories that may be displayed in such a submenu include,
but are not limited to: 1) "Natural Gas;" 2) "Water/Sewer;" 3) "Power
Line;" 4) "Phone Line;" 5) "CATV Line;" and 6) "Other."

[0255]While the foregoing discussion of landmark categories and types
provides one construct in which a wide variety of landmarks are made
available for selection by the technician, it should be appreciated that
in other implementations, options for landmark selection may be presented
in different manners. For example, a more succinct list of landmark types
may be presented to the technician to facilitate easy selection (e.g., a
more limited set of about a dozen more common landmark types that might
be encountered in the field, such as "telephone pole," "fire hydrant,"
"meter," "manhole," "curb," etc.). More generally, any number and variety
of landmark types may be presented to the technician via the user
interface in alphabetically ordered lists, numerically ordered lists, or
other types of ordered text-based or symbolic arrangements, for example.

[0256]In another exemplary implementation, the categories and/or types of
landmarks made available for selection via the user interface may be
based at least in part on a type of facility being marked when the
marking device was in a marking mode prior to selection of the landmark
mode. For example, consider a technician using the marking device in the
marking mode and in the process of marking a power line. In one
implementation, upon switching to landmark mode, the user is first
presented with selection options for landmark category and/or type that
are more closely related to a power line (e.g., a more limited subset of
option types including "pole," "transformer," "pedestal," etc.). In one
aspect, the technician may nonetheless still have the option to select
other categories and/or types of landmarks, but as a default the
technician is first presented with options related to the type of
facility last being marked. In another aspect, the selection options for
landmark category and/or type may be specifically and intentionally
limited to those options that are most germane to the type of facility
last being marked in the previous marking mode (i.e., immediately prior
to entry into the landmark mode).

[0257]In yet another exemplary implementation, the user interface may
include a microphone and the processor may be configured to accept and
process audible commands, such that landmark category and/or type
selection may be accomplished via voice-activated commands. For example,
once landmark mode is selected, the technician may select a particular
landmark category or type by simply speaking into the microphone (e.g.,
"telephone pole," "fire hydrant," "meter," "manhole," "curb," etc.).

[0258]In addition to, or as an alternative to, selection of landmark
category and/or type, block 618 may provide for the entry of any of a
variety of text information for inclusion as part of the landmark
information in an electronic record. For example, in some exemplary
implementations, via the user interface and/or display the technician may
enter text-based information relating to an environmental landmark (e.g.,
as an offset to another topological, architectural, or infrastructure
feature in proximity to the environmental landmark--"telephone pole 5 ft.
from back of curb"). Additionally, in a manner similar to landmark type
selection, the user interface/display may provide for menu-driven
selection via a GUI of predetermined options for additional text-based
information to be included as part of the landmark information (e.g., a
set of "stock" text messages for selection to be included as part of
landmark information).

[0259]Following selection of landmark category and/or type, and/or
entry/section of any text-based information in block 618 of the process
1200 shown in FIG. 12, in block 620 actuations of the actuator 142 in
landmark mode cause the processor to collect various "landmark
information" with each actuation, which information is logged in an
electronic record as a "landmark event entry" (rather than an actuation
event entry, as noted in Table 3 above). Furthermore, as noted above, the
processor 118 and/or the link transmitter 168 of the actuation system 120
may be particularly configured to either dispense or not dispense marking
material upon actuations in landmark mode. Essentially, in landmark mode,
the technician positions the marking device proximate to a selected
category/type of landmark and actuates the actuator to acquire various
information relating to the landmark (e.g., geo-location data, type, time
stamp).

[0260]In general, the processor may be configured to communicate with
(e.g., poll) any of a variety of input devices to collect landmark
information to be logged in an electronic record. As discussed above in
connection with the marking mode (refer again to FIG. 2), such
information may be acquired from any of a variety of input devices
including, but not limited to, the location tracking system 130, the
timing system 128, the communications interface 124 (e.g., a USB port or
other port), the user interface 126, and the local memory 122.

[0261]In particular, any data that is available from the location tracking
system (e.g., any information available in various NMEA data messages,
such as coordinated universal time, date, latitude, north/south
indicator, longitude, east/west indicator, number and identification of
satellites used in the position solution, number and identification of
GPS satellites in view and their elevation, azimuth and SNR values,
dilution of precision values) may be collected as landmark information
and logged in an electronic record as part of a landmark event entry.
Additionally, information collected from the user interface in the form
of a text entry by the technician may be included in a landmark event
entry; for example, in one implementation, upon actuation of the
actuator, the processor may prompt the technician via the display of the
user interface to enter text notes, if desired (e.g., the technician may
describe an offset of a target environmental landmark from an
architectural, topographical, or infrastructure feature to compliment
geographic information provided by the location tracking system), and
this textual information may serve as landmark information. In view of
the foregoing, it should be appreciated that "landmark information" may
include a wide variety of information components including, but not
limited to, one or more of geographical information (e.g., from the
location tracking system), timing information (e.g., from the location
tracking system and/or the timing system), landmark category and/or type
information (e.g., selected or entered via the user interface), textual
information (e.g., entered via the user interface), or other information
(e.g., received from the local memory and/or the communications
interface).

[0262]Table 9 below provides an example of content and format for a
landmark event entry that may be logged in a file for an electronic
record and/or transmitted by the marking device when in landmark mode.
The example landmark event entry shown below in Table 9 also follows a
similar format to that used for the event entry examples provided in
Tables 2-5 above.

[0263]In the example landmark event entry given in Table 9, the landmark
information includes a time stamp (e.g., DATE and TIME), geographical
information (e.g., GPS data), category/type information, and text-based
information for an environmental landmark. The notation LMRK (3,12) in
the example denotes a category 3, type 12 landmark which, in the
exemplary listings provided above, corresponds to "Power Line," "Circuit
Breaker." It should be appreciated that the event entry shown in Table 9
is provided primarily for purposes of illustration, and that a variety of
other or additional landmark information may be included in landmark
event entries, as noted above.

[0264]As with the event entry examples provided in Tables 2-5 above, the
exemplary format for a mode select and landmark event entry as shown in
Tables 8 and 9 may be included in either an ASCII and XML file format for
an electronic record that is stored and/or transmitted by the marking
device (in which a particular naming scheme/format may be adopted to
identify files/electronic records, such as "ServerID_WandID_Job ID"). It
should also be appreciated that an electronic record generated by a
multi-mode marking device in some instances may include a mixture of
actuation event entries and landmark event entries, actuation event
entries without any landmark event entries, and landmark event entries
without any actuation event entries.

[0265]Yet another alternative format for storing and organizing landmark
information in an electronic record, according to one embodiment of the
invention, is shown in Tables 10 and 11 below. By way of example, Table
10 shows the format and content of an electronic record entry for a
utility pole, which includes one geo-location data point, and Table 11
shows the format and content of an electronic record entry for a
pedestal, which includes four geo-location data points (i.e., one for
each corner of the pedestal). It should be appreciated that the format
and content shown below in Tables 10 and 11 is provided primarily for
purposes of illustration and, as noted above, a variety of format and
content may be included in an electronic record entry for landmark
information. The examples provided in Tables 10 and 11 may constitute an
"original" electronic record generated by the processor pursuant to the
process 1200 shown in FIG. 12, or may be derived from raw data collected
and logged pursuant to the process 1200 (e.g., as a flat file, an ASCII
formatted file, or an XML formatted file) and subsequently reorganized
and particularly formatted. It should also be appreciated that the
examples provided in Tables 10 and 11 illustrate that landmark
information may be included in an electronic record together with one or
both of ticket information and service-related information, as discussed
above in connection with electronic records including various marking
information.

[0266]FIG. 13 is a block diagram similar to FIG. 10 and illustrates an
exemplary data structure for an electronic record 135 that includes both
marking information and landmark information (i.e., that may be generated
by and/or based on information collected during the process 1200
discussed above in connection with FIG. 12 and based on the organization
of information shown in Tables 9 and 10 above). Like the exemplary
electronic record shown in FIG. 10, the record 135 in FIG. 13 includes a
file identifier 701 (e.g., one or more of Job ID, WandID, ServerID, etc.)
and a plurality of actuation data sets 1 through N (with reference
numbers 702A, 702B, 702C . . . 702N), wherein each actuation data set is
associated with a corresponding actuation of a marking device. In FIG.
13, also as in FIG. 10, additional details of the data structure for
actuation data set 3 702C are shown, relating to marking information
collected in marking mode. However, unlike FIG. 10, FIG. 13 shows that
the actuation data set 2 702B relates to landmark information acquired
pursuant to an actuation in landmark mode; in particular, the actuation
data set 2 702B includes a date/time field 1702, a type field 1704, and a
geo-location field 1706 corresponding to a landmark event entry.

[0267]In other respects, the data structure in FIG. 13 is similar to that
shown in FIG. 10. For example, various other information that may be
common to multiple (or all) actuation data sets of a given electronic
record may be stored in one or more additional elements of the electronic
record that are not contained within one or more of the actuation data
sets themselves (e.g., one or more of the ticket information field 714,
the service-related information field 716, and the marking material
properties field 710, which are shown as part of the data structure for a
given actuation data set of the electronic record, may instead be
elements of the electronic record that are common to all actuation data
sets of a given electronic record).

[0268]Once an actuation of the marking device in landmark mode has been
logged as a landmark event entry, the process 1200 shown in FIG. 12
returns to block 610. At this point, the technician is provided (via the
user interface/display) with the options of pausing the job (block 610),
restarting the job if previously paused (block 612), stopping the job and
indicating completion (block 614) or selecting landmark mode again (block
616) for the next actuation. If the technician selects none of these
options, the process returns to block 608, at which point further polling
and/or interrupt events are logged (i.e., an actuation event entry
capturing marking information is logged with the next actuation of the
actuator), as discussed above in connection with FIG. 9. Accordingly,
after an actuation in landmark mode, in one exemplary implementation the
marking device defaults back to the marking mode, unless and until the
technician selects the landmark mode again for a subsequent actuation.

[0269]In an alternative implementation not shown in FIG. 12, following
actuation of the marking device in landmark mode, the processor may
control the user interface/display to provide an option to the technician
to exit landmark mode (rather than automatically presenting the options
of pause job, restart job, stop job, or landmark mode). In this manner,
the marking device remains in landmark mode for subsequent actuations
until the technician makes a menu selection to exit landmark mode, at
which point the process 1200 returns to block 610.

[0270]In yet another embodiment, the processor 118, executing marking data
algorithm 134 in landmark mode, may be configured to generate an
essentially continuous stream of data packets representing various event
entries logged by the marking device (e.g., as shown above in Tables
2-9). As discussed above in connection with the marking mode, each data
packet may include a header, one or more flag fields, and one or more
information payload fields. To accommodate both a marking mode and a
landmark mode, one flag field may be set or reset upon selection of the
landmark mode so as to identify the contents of any information payload
field in the data packet as landmark information as opposed to marking
information. Similarly, as discussed above, one or more other flag fields
may be set (or reset) upon occurrence of one or more predetermined
interrupt events (e.g., pull/depress actuator, release actuator, marking
dispenser in, marking dispenser out, low power, communication link fail,
etc.). In this manner, a continuous stream of data may be provided as an
output by the processor, in which certain interrupt events, such as an
actuation and/or release of the actuator, "tag" certain data packets via
an interrupt flag, and certain data packets also may be tagged as
generated in marking mode or landmark mode. In yet other aspects of this
embodiment, all data packets thusly generated may be stored in the file
opened for the electronic record and/or transmitted from the marking
device in essentially real time; alternatively, only certain data packets
with one or more predetermined flags set may be stored and/or
transmitted.

[0271]Thus, in landmark identification mode, a locate technician may
employ an appropriately configured marking device to capture the types
and locations of environmental landmarks of interest that are present at
the work site and/or in the general environs of a dig area. While in
landmark mode, the locate technician may approach a certain environmental
landmark, then select the type of the environmental landmark via user
interface, position the marking device (e.g., place the tip of marking
device) proximate to the target environmental landmark, and then actuate
the marking device. In doing so, the marking device logs in an electronic
record landmark information including, for example, the type of the
target environmental landmark, the geo-location of the target
environmental landmark, and a time stamp in an electronic record. The
locate technician may move from one environmental landmark to the next
until information about all environmental landmarks of interest has been
captured. Additionally, one or more data points (e.g., "landmark event
entries") may be captured for any given environmental landmark.

[0272]With reference again to FIGS. 2 and 3, in yet another embodiment the
processor 118, executing marking data algorithm 134, and/or one or more
remote computers 150 executing marking data algorithm 134, may
additionally process various marking information and/or landmark
information provided in real time from a marking device and/or stored in
an electronic record of a marking operation and control a display device
(e.g., display 146 of marking device 110 or some other display device) to
render a computer-generated visual representation of one or both of the
marking information and landmark information. Such a visual
representation may be used, for example, to provide immediate feedback to
the locate technician, provide essentially real-time feedback to a
supervisor monitoring the technician from a remote location, provide a
visual record of the marking information and/or the landmark information
(e.g., for archiving purposes, once one or more electronic records are
generated), and/or to verify the quality (e.g., accuracy and
completeness) of work performed during a locate and marking operation.
For purposes of the following discussion, a "marking operation" may refer
to one or both of the processes of collecting marking information and
landmark information. Accordingly, it should be appreciated that in
various exemplary implementations of a computer-generated visual
representation, only marking information may be visually rendered, only
landmark information may be visually rendered, or both marking
information and landmark information may be visually rendered.

[0273]In various aspects of this embodiment, a visual representation may
be static in that all available marking information and/or landmark
information is presented in a display field at one time after generation
of an electronic record; alternatively, the visual representation may be
dynamic in that marking information and/or landmark information is
displayed in essentially real-time as it is collected, or may be
displayed after generation of the electronic record in a time-sequenced
animation that "recreates" the collection of information on the time
scale in which it was originally acquired (e.g., based on the time stamps
indicating when the information was acquired).

[0274]In other aspects, the relative positions of all locate marks
represented by actuation event entries logged and/or transmitted by the
marking device, as well as the relative positions of all environmental
landmarks represented by landmark event entries logged and/or transmitted
by the marking device, may be displayed (e.g., based on geo-location data
and some appropriate scale of an available display field of display 146)
to provide a visual representation of the marking operation. A visual
representation of a marking operation may also be rendered in one or more
particular colors corresponding to one or more particular underground
facilities marked during the marking operation (e.g., see Table 7).

[0275]In one exemplary implementation, such a visual representation may
include one "electronic locate mark" displayed in a display field for
each actuation/dispensing action of a marking device, such that there is
essentially a one-to-one correspondence between electronic locate marks
and physical locate marks for a given underground facility marked during
a marking operation. Alternatively, in another exemplary implementation
of such a visual representation, an essentially continuous solid line (or
other line type) may be displayed in a display field to represent a given
underground facility marked during a marking operation. In another
aspect, the processor may process the geo-location data in respective
marking actuation data sets of an electronic record so as to filter,
average, interpolate and/or otherwise "smooth" data (e.g., so as to
provide "cleaner" visual renderings and/or connect successive locate
marks represented by the respective actuation data sets of the electronic
record); alternatively, "raw data" provided by the marking device may be
utilized for the visual representation. In yet another aspect of this
embodiment, visual representations of multiple marking operations for
different underground facilities within the same work site/dig area may
be generated in the same display field of a display device so as to
provide a composite visual representation, in which different underground
facilities may be uniquely identified in some manner (e.g., by different
line types and/or different colors), and one or more environmental
landmarks in and/or around the work site/dig area may be identified using
a variety of displayed identifiers (e.g., icons, symbols, marks, shapes,
etc.).

[0276]FIG. 14 illustrates a flow chart for a process 800 according to one
embodiment of the present invention for generating a visual
representation of a marking operation based on an electronic record
and/or essentially real-time information transmission from the marking
device 110. As noted above, the process 800 may result from the execution
of various embodiments of the marking data algorithm 134 on the processor
118 of the marking device 110 (to render the visual representation on the
display 146 of the marking device), or by one or more other remote
computers (to render the visual representation on one or more other
display devices).

[0277]In block 802 of the process 800, if an electronic record has already
been generated for the marking operation in which one or more underground
facilities are marked and/or environmental landmark information is
acquired, the record is examined to determine the geographic extents of
the locate marks and/or environmental landmarks to be visually rendered
on a display device. In particular, the processor 118 may review the
geo-location data of all actuation data sets of the electronic record to
determine (e.g., based on the respective latitude and longitude
coordinates of the available geo-location data) the maximum extents of
the marking operation to be visually rendered.

[0278]The maximum extents of the marking operation may be determined in
any of a variety of manners according to different exemplary
implementations. For example, in one exemplary implementation, in block
802 the processor 118 may determine the centroid of all electronic locate
marks and/or environmental landmarks represented by respective actuation
data sets of the electronic record to be displayed. The processor then
determines the geographic extent of the collection of electronic locate
marks and/or environmental landmarks by determining one or more
latitude/longitude coordinate pairs from the available data having a
greatest distance from the centroid. In one example, the processor may
determine a single farthest point from the centroid, and a distance
between this farthest point and the centroid serves as a radius of a
circle that provides an "extents area circle." In another example, the
"farthest opposing corners" of a rectangle around the centroid may be
determined by assigning the centroid as the origin of a reference
coordinate system, and finding the coordinate pairs in opposing quadrants
of the coordinate system having a greatest distance from the centroid
(e.g., the +LAT/+LONG and -LAT/-LONG coordinate pairs at a greatest
distance from the origin) to provide an "extents area rectangle." Other
types of polygons and closed shapes (ovals) may be employed to provide an
extents area for the marking operation to be displayed.

[0279]Alternatively, if an electronic record has not been previously
generated and information received in essentially real-time from the
marking device is to be displayed in a display field, a default extents
area may be selected in advance based on any of a variety of criteria.
For example, address and/or site description information provided in a
ticket pursuant to which the marking operation is performed may provide a
basis on which an extents area for the marking operation may be estimated
a priori. Similarly, as discussed further below in connection with FIG.
17, an available digital image of the work site/dig area may be employed
to determine or estimate an initial extents area for the marking
operation.

[0280]In block 804, the extents area of the marking operation to be
visually rendered is then mapped to an available display field of a
display device, using any appropriate scaling factor as necessary, to
ensure that all of the geo-location data in the electronic record fits
within the display field. For example, in one exemplary implementation, a
transformation may be derived using information relating to the available
display field (e.g., a reference coordinate system using an appropriate
scale for a given display field of a display device) to map data points
within the extents area to the available display field. In another aspect
of this example, a buffer area around the extents area may be added to
provide one or more suitable margins for the displayed visual
representation, and/or to accommodate different shapes of extents areas
to the available display field of the display device, and an appropriate
transformation may be derived based on this optional additional buffer
area.

[0281]Once a transformation is derived to map the marking operation
extents area to the available display field of a display device, in block
806 one or more electronic locate marks and/or one or more identifiers
(e.g., icons, symbols, marks, shapes, etc.) for environmental landmarks
is/are rendered in the display field based on applying the transformation
to the geo-location data present in the data set of one or more
corresponding actuation data sets of the electronic record. In one
exemplary implementation, one electronic locate mark is rendered in the
display field for each actuation data set of an electronic record. With
reference again to Table 6 and FIG. 10, in one embodiment each actuation
data set includes at least T1 geo-location data for a start of an
actuation of a marking device and one or more other pieces of
geo-location data during actuation. Using multiple pieces of geo-location
data per actuation data set, an electronic locate mark may be rendered as
a line in the display field (e.g., so as to visually represent one of the
physical locate marks 414-1, 414-2 or 414-3 shown in FIG. 8). In another
exemplary implementation, an electronic locate mark may be rendered for
each geo-location data in a given entry, such that multiple electronic
locate marks correspond to one actuation (e.g., a series of dots
electronically rendered to graphically represent a line-type physical
locate mark). In one aspect, as discussed above, a given electronic
locate mark may be rendered in a particular color and/or line type to
represent a type of underground facility represented by the mark (e.g.,
as indicated by marking material information included in the electronic
record).

[0282]FIG. 15 illustrates a plan view of an exemplary composite visual
representation 900 that "electronically recreates" a marking operation
for various underground facilities and environmental landmarks present in
a work site/dig area, based for example on the process 1200 discussed
above in connection with FIG. 12. In particular, FIG. 15 illustrates a
number of electronic locate marks corresponding to actuations of a
marking device whose relative positions in the display field are derived
from marking actuation data sets of the electronic record, as discussed
above. In the example of FIG. 15, act-1 through act-7 form a lines
pattern 910 representing a first marked underground facility, act-8
through act-14 form a lines pattern 912 representing a second marked
underground facility, act-15 through act-24 form a lines pattern 914
representing a third marked underground facility, and act-25 through
act-34 form a lines pattern 916 representing a fourth marked underground
facility. FIG. 15 also includes identifiers for various environmental
landmarks disposed in proximity to the electronic locate marks; in
particular, a building 950 is shown in the top portion of FIG. 15,
whereas two utility poles 952 and 954, as well as a fire hydrant 956, are
shown in the bottom portion of FIG. 15.

[0283]As noted above, while in one embodiment there may be a one-to-one
correspondence between electronic locate marks rendered in a single or
composite visual representation and physical locate marks placed in a dig
area during a marking operation, or there may be multiple electronic
locate marks for a corresponding physical locate mark, in yet other
embodiments a single or composite visual representation may provide a
variety of other indicators/digital representations of marked underground
facilities in a computer-generated visual rendering. For example, FIG. 16
illustrates another example of a composite visual representation 1000
based on the same electronic record used to generate the composite visual
representation 900 of FIG. 15, in which continuous lines are used to
indicate the respective marking operations. To this end, in one exemplary
implementation, an additional step may be included in the process 800
shown in FIG. 14, in which the processor may process the marking
geo-location data in an electronic record by filtering, averaging,
interpolating and/or otherwise "smoothing" the data so as to connect
successive discrete locate marks represented by the respective actuation
data sets of the electronic record and thereby provide a substantially
smooth continuous line for display.

[0284]Similarly, filtering, averaging, interpolating, processing and/or
otherwise smoothing of data may be applied to landmark information
captured in landmark event entries. For example, multiple event entries
logged for a particular environmental landmark (e.g., the four corners of
a pedestal) may be processed so as to provide a single point in a display
field at which to display a symbol, icon or other identifier for an
environmental landmark. Such processing may include, for example,
selecting any one of multiple geo-location coordinates captured in
multiple event entries as representative of the landmark location,
calculating a centroid of all points represented by captured coordinates,
"pre-filtering" a collection of coordinates to eliminate significant
"outliers" and subsequently determining a centroid of the remaining
coordinates, etc.

[0285]In the example of FIG. 16, as also noted above, different
underground facility types may be indicated in different color lines, and
the different colors/facility types may be derived from the electronic
record (e.g., based on the correlations provided in Table 7).
Furthermore, in other aspects, text indicators may be included in the
visual representation, and/or other types of coding may be used
(different line styles such as patterns, width, bold, etc.; a succession
of symbols or other graphic icons, etc.) to indicate different facility
types, and/or some other aspect of a given facility (e.g., the material
used for a particular pipe, conduit, cable, sheathing; the diameter of a
particular pipe, conduit, cable; offsets to one or more environmental
landmarks, etc.). By way of example, FIG. 16 indicates that the four
underground facilities in the composite visual representation correspond
to a power line 1010 (which may be rendered in the color red), a first
sewer line 1012 (which may be rendered in the color green), a second
sewer line 1014 (which also may be rendered in the color green), and a
telecommunications line 1016 (which may be rendered in the color orange).
An exemplary composite visual representation may include additional
textual, numeric and/or graphic elements to provide other information
available in the electronic record for the marking operations (e.g.,
timestamp information, ID information, coordinates for location
information, offset indications, etc.). For example, in FIG. 16 an offset
958 of 3 feet is indicated between the fire hydrant 956 and the sewer
line 1014.

[0286]In some marking operations, a technician may use the marking device
not only to mark an underground facility's placement/path relative to the
ground, pavement or other surface, but also to "annotate" the marking
operation in some fashion. For example, in some instances a technician
actually "writes" with the marking device (e.g., by actuating the marking
device to dispense paint) to provide text annotations, offset
indications, arrows, other symbols, and the like on the ground, pavement
or other surface. Accordingly, the electronic record for a marking
operation may include one or more actuation data sets corresponding to
actuations in which the technician was "writing" to annotate the marking
operation in some fashion rather than marking the path of an underground
facility. In some cases, providing such technician annotations on a
visual representation of a marking operation may be desirable; however,
in other instances such annotations may provide erratic markings on a
visual representation, in which case additional processing of
geo-location data or other information in the electronic record (e.g.,
filtering, averaging, interpolating and/or otherwise "smoothing" the
data) may be employed.

[0287]In yet another embodiment, a single or composite visual
representation of a marking operation, including one or both of marking
information and landmark information, may be rendered on a display device
together with a digital image representative of at least a portion of a
dig area at a work site, such that one or more electronic locate marks
and/or one or more identifiers for environmental landmarks appear in
appropriate relative positions overlaid on the displayed digital image.
FIG. 17 illustrates yet another example of a composite visual
representation 1100, albeit based on an electronic record different than
that used to generate the visual representations of FIGS. 15 and 16, in
which continuous lines are used to indicate the respective different
underground facilities marked, and these lines are overlaid on a digital
image of a dig area, together with identifiers for environmental
landmarks. It should be appreciated that although continuous lines
representing underground facilities are depicted on a digital image in
FIG. 17, in other embodiments discrete electronic locate marks
corresponding to successive actuations of a marking device (or multiple
discrete electronic locate marks per actuation) may be overlaid on a
digital image of the dig area.

[0288]In the embodiment of FIG. 17, a number of different image sources
and image types may be employed to provide the digital image on which a
visual representation of a marking operation may be overlaid. For
purposes of the present disclosure, such a digital image (also referred
to herein as an "input image") may be any image represented by source
data that is electronically processed (e.g., the source data is in a
computer-readable format) to display the image on a display device. An
input image may include any of a variety of paper/tangible image sources
that are scanned (e.g., via an electronic scanner) or otherwise converted
so as to create source data (e.g., in various formats such as XML, PDF,
JPG, BMP, etc.) that can be processed to display the input image. An
input image also may include an image that originates as source data or
an electronic file without necessarily having a corresponding
paper/tangible copy of the image (e.g., an image of a "real-world" scene
acquired by a digital still frame or video camera or other image
acquisition device, in which the source data, at least in part,
represents pixel information from the image acquisition device).

[0289]In some exemplary implementations, input images according to the
present disclosure may be created, provided, and/or processed by a
geographic information system (GIS) that captures, stores, analyzes,
manages and presents data referring to (or linked to) location, such that
the source data representing the input image includes pixel information
from an image acquisition device (corresponding to an acquired "real
world" scene or representation thereof), and/or spatial/geographic
information ("geo-encoded information").

[0290]In view of the foregoing, various examples of input images and
source data representing input images according to the present
disclosure, to which the inventive concepts disclosed herein may be
applied, include but are not limited to: [0291]Manual "free-hand" paper
sketches of the geographic area (which may include one or more buildings,
natural or man-made landmarks, property boundaries,
streets/intersections, public works or facilities such as street
lighting, signage, fire hydrants, mail boxes, parking meters, etc.);
[0292]Various maps indicating surface features and/or extents of
geographical areas, such as street/road maps, topographical maps,
military maps, parcel maps, tax maps, town and county planning maps,
call-center and/or facility polygon maps, virtual maps, etc. (such maps
may or may not include geo-encoded information); [0293]Facility maps
illustrating installed underground facilities, such as gas, power,
telephone, cable, fiber optics, water, sewer, drainage, etc. Facility
maps may also indicate street-level features (streets, buildings, public
facilities, etc.) in relation to the depicted underground facilities.
Examples of facility maps include CAD drawings that may be created and
viewed with a GIS to include geo-encoded information (e.g., metadata)
that provides location information (e.g., infrastructure vectors) for
represented items on the facility map; [0294]Architectural, construction
and/or engineering drawings and virtual renditions of a space/geographic
area (including "as built" or post-construction drawings); [0295]Land
surveys, i.e., plots produced at ground level using references to known
points such as the center line of a street to plot the metes and bounds
and related location data regarding a building, parcel, utility, roadway,
or other object or installation; [0296]A grid (a pattern of horizontal
and vertical lines used as a reference) to provide representational
geographic information (which may be used "as is" for an input image or
as an overlay for an acquired "real world" scene, drawing, map, etc.);
[0297]"Bare" data representing geo-encoded information (geographical data
points) and not necessarily derived from an acquired/captured real-world
scene (e.g., not pixel information from a digital camera or other digital
image acquisition device). Such "bare" data may be nonetheless used to
construct a displayed input image, and may be in any of a variety of
computer-readable formats, including XML); [0298]Photographic
renderings/images, including street level, topographical, satellite, and
aerial photographic renderings/images, any of which may be updated
periodically to capture changes in a given geographic area over time
(e.g., seasonal changes such as foliage density, which may variably
impact the ability to see some aspects of the image); and [0299]An image,
such as any of the above image types, that includes one or more dig area
indicators, or "virtual white lines," that provide one or more
indications of or graphically delimit a dig area, as described in U.S.
patent application Ser. No. 12/366,853, published as U.S. Patent
Publication 2009-0238417-A1, incorporated by reference herein. The
virtual white lines may include lines, drawing shapes, shades, symbols,
coordinates, data sets, or other indicators that are added to an image,
and may assist a locate technician in the performance of a locate
operation by identifying the area of interest, i.e., the dig area. In
this manner, a searchable electronic record according to the concepts
disclosed herein may be generated based on a previously marked-up input
image on which the dig area is indicated.

[0300]It should also be appreciated that source data representing an input
image may be compiled from multiple data/information sources; for
example, any two or more of the examples provided above for input images
and source data representing input images, or any two or more other data
sources, can provide information that can be combined or integrated to
form source data that is electronically processed to display an image on
a display device.

[0301]As noted above, in some implementations an input image may be
indexed to Global Positioning System (GPS) coordinates or another
coordinate system that provides geo-spatial positioning. An input image
may include geo-coding or other geographical identification metadata and
may be provided in any computer-readable format. An input image may also
include images of map symbols, such as roads and street names, that may
be superimposed upon or displayed separately from an underlying
geographic area when the input image is displayed on a display device.

[0302]Based on the foregoing, a digital image may be displayed in an
available display field of a display device either before or after
electronic locate marks and/or identifiers for environmental landmarks
are displayed in the available display field. For example, in one
implementation, after the block 806 in FIG. 14, all or a portion of the
digital image may be mapped to the available display field based on any
relevant geographic information accompanying the digital image (e.g., GPS
coordinates to which the image is indexed). Alternatively, the digital
image may be mapped first to the available display field of the display
device depending on appropriate scaling and/or transformation parameters
as would be readily appreciated by one of ordinary skill in the art, and
thereafter one or more electronic locate marks and/or one or more
identifiers for environmental landmarks similarly may be mapped to the
available display field in appropriate positions relative to the
underlying digital image. In the example of FIG. 17, a first visual
representation of a gas line 1130 is depicted, a second visual
representation of a communication line 1120 is depicted, and a third
visual representation of an electric line 1110 is depicted on an aerial
image of a residential dig area for purposes of illustration. As
discussed above in connection with other embodiments, these visual
representations may be displayed in different colors and/or line types to
denote different types of underground facilities and/or various
attributes of a given facility. As also illustrated in FIG. 17, other
types of markings may be included as part of the displayed image,
including various environmental landmarks such as junction boxes or
transformers 1140, streets, property boundaries, tie-downs (reference
lines between marked facilities and environmental landmarks and/or
property boundaries) and their associated dimensions, and one or more
text boxes 2173 (e.g., to indicate an address of the work site over the
residence), and the like.

[0303]In some implementations, marking information and landmark
information, if displayed together, may be differentiated in a display
field in any of a variety of manners (e.g., different line types, symbols
or patterns; different colors or shades of related colors; artificially
offset from each other in the display field if marking information and
landmark information overlap or are sufficiently close to each other in
some instances, etc.) to allow for sufficient visual perception of both
marking information and landmark information.

[0304]Additionally, in one embodiment, each of marking information and
landmark information, if present in a computer-aided visual rendering, as
well as any constituent information forming part of the marking
information and landmark information, may be displayed as separate
"layers" of the visual rendering, such that a viewer of the visual
rendering may turn on and turn off displayed information based on a
categorization of the displayed information. FIG. 18 shows a generic
display device 1800 having a display field 3005 with exemplary content
for purposes of explaining some concepts germane to display layers,
according to one embodiment. For example, all marking information may be
categorized generally under one layer designation 3030 ("marking layer")
and independently enabled or disabled for display accordingly, and all
landmark information may be categorized generally under yet another layer
designation 3040 ("landmark layer") and independently enabled or disabled
for display accordingly. Respective layers may be enabled or disabled for
display in any of a variety of manners; for example, in one
implementation, a "layer directory" or "layer legend" pane 3010 may be
included in the display field 3005 (or as a separate window selectable
from the display field of the visual rendering), showing all available
layers, and allowing a viewer to select each available layer to be either
displayed or hidden, thus facilitating comparative viewing of layers.

[0305]Furthermore, any of the above-mentioned general categories for
layers may have sub-categories for sub-layers, such that each sub-layer
may also be selectively enabled or disabled for viewing by a viewer. For
example, under the general layer designation of "marking layer,"
different facility types that may have been detected during a marking
operation (and indicated in the marking information by color, for
example) may be categorized under different sub-layer designations (e.g.,
designation 3032 for "marking layer--electric;" designation 3034 for
"marking layer--gas;" etc.); in this manner, a viewer may be able to hide
only the electric marking information while viewing the gas marking
information, or vice versa, in addition to having the option to view or
hide all marking information. Sub-layer designations similarly may be
employed for the landmark information (e.g., designation 3042 for
"landmark layer--water/sewer;" designation 3044 for "landmark
layer--CATV;" designation 3046 for "landmark layer--buildings"). As shown
in the example of FIG. 18, both the marking and landmark layers are
enabled for display; amongst the illustrated sub-layer designations, only
the "electric" sub-layer of the marking layer is enabled for display, and
only the "buildings" sub-layer of the landmark layer is enabled for
display. Accordingly, using the exemplary composite visual representation
1000 shown in FIG. 16 as a baseline for purposes of illustration, only
the power line 1010 appears in the electronic rendering 1000A shown in
FIG. 18 as a constituent element of the electric sub-layer of the marking
layer, together with the building 950.

[0306]Virtually any characteristic of the information available for
display may serve to categorize the information for purposes of display
layers or sub-layers. In particular, any of the various exemplary
constituent elements of marking information discussed herein (e.g.,
timing information, geographic information, service-related information,
ticket information, marking material information, environmental
information, and operational information, the latter two of which are
discussed in greater detail further below) may be categorized as a
sub-layer, and one or more sub-layers may further be categorized into
constituent elements for selective display (e.g., as sub-sub-layers).
Similarly, any of the various exemplary constituent elements of landmark
information discussed herein (e.g., geo-location data of an environmental
landmark, type of environmental landmark, a time stamp for any acquired
information relating to an environmental landmark) may be categorized as
a sub-layer (and any sub-layer may be further categorized into
sub-sub-layers, and so on).

[0307]It should further be appreciated that, according to various
embodiments, the attributes and/or type of visual information displayed
as a result of selecting one or more layers or sub-layers is not limited.
In particular, visual information corresponding to a selected layer or
sub-layer may be electronically rendered in the form of one or more lines
or shapes (of various colors, shadings and/or line types), text, graphics
(e.g., symbols or icons), and/or images, for example Likewise, the visual
information corresponding to a selected layer or sub-layer may include
multiple forms of visual information (one or more of lines, shapes, text,
graphics and/or images).

[0308]As a non-limiting illustrative example, a "marking" layer may
include respective sub-layers of different facility types marked, in
which respective facility types are rendered on the display as lines
having different colors, line types and/or shading. A "temperature"
sub-layer of a "marking" layer may include ground temperatures sensed
during marking of respective facility types, in which sensed temperatures
are rendered on the display as an icon/symbol in combination with text
(e.g., a snowflake accompanied by a text label "15 deg. F") in proximity
to the visual rendering of the marked facility. From the foregoing, it
may be appreciated that a wide variety of information may be categorized
in a nested hierarchy of layers, and information included in the layers
may be visually rendered, when selected/enabled for display, in a variety
of manners.

[0309]In addition to the marking information and/or the landmark
information, in yet other embodiments in which a digital image is
rendered in the display field (e.g., as shown in FIG. 17), the image
information on which the digital image is based may be categorized as a
display layer, such that the marking information, landmark information,
and image information may be selectively enabled or disabled for display
as a display layer. In this manner, the displayed digital image on which
one or both of marking information and landmark information may be
overlaid (and in some instances constituent elements thereof) may be
toggled on and off conveniently for comparative display.

[0310]In one exemplary implementation, all image information may be
categorized generally under one layer designation (e.g., "Reference"--see
designation 3050 in FIG. 18), and independently enabled or disabled for
display (e.g., hidden) accordingly. Similarly, while not shown in FIG.
18, in some implementations all information available for overlay,
including both marking information and landmark information if available,
may be categorized generally under another layer designation (e.g.,
"Field") and independently enabled or disabled for display; accordingly,
it should be appreciated that in one aspect of this alternative
implementation, under the general layer designation of "Field," the
marking information may be categorized as one sub-layer of the Field
layer (in some cases with additional associated marking sub-sub-layers)
and the landmark information may be categorized as another sub-layer of
the Field layer (in some cases with additional associated landmark
sub-sub-layers).

[0311]Like the "Field" layer, the "Reference" layer similarly may have one
or more sub-layers for various constituent elements of the image
information upon which the digital image is rendered. Virtually any
number of possible sub-layers may be accordingly designated, based at
least on the various examples of image information discussed above (e.g.,
maps, such as road maps or facilities maps; dig area indicators, either
alone or forming part of a digital image; grids, either alone or forming
part of a digital image; engineering or architectural drawings;
photographic renderings; etc.--any of which may have constituent elements
of information that respectively may be categorized as image or
"Reference" sub-layers). To provide illustrative non-limiting examples of
sub-layers of the "Reference" layer, FIG. 18 indicates a "digital image"
sub-layer with the designation 3052, a "dig area indicator(s)" sub-layer
with the designation 3054, and a "grid" sub-layer with the designation
3056.

[0312]The various examples of visual representations illustrated in FIGS.
15-18 may be used for various purposes, including, but not limited to:
[0313](1) The display may be viewed by the marking technician for
substantially immediate feedback of his/her work performed, which can be
compared against the ticket information to ensure that the full scope of
the current marking operation has been completed satisfactorily.
[0314](2) The display may be viewed by a supervisor (using remote
computer 150 that is receiving the data) as substantially immediate
feedback of work performed by the marking technician, which again can be
compared against the ticket information to ensure that the full scope of
the current marking operation has been completed satisfactorily. When the
supervisor is viewing the marking operation in real time, he/she may
contact the marking technician in real time in the event that the marking
operation is unsatisfactory; [0315](3) The display may be viewed by a
quality control supervisor (using remote computer 150 that has received
the data) as feedback of work performed by the technician, which again
can be compared against the ticket information to ensure that the full
scope of the current marking operation has been completed satisfactorily.
By viewing the marking operation, the quality control supervisor may
dispatch a quality control technician or other personnel in the event
that there is the marking operation is unsatisfactory, and [0316](4) The
display may be viewed by a training supervisor as feedback of work
performed by the marking technician, which can be used to assess employee
performance and direct training activities.

[0317]According to another aspect of the present invention, a marking
device includes one or more environmental and/or operational sensors,
which constitute additional examples of input devices from which marking
information may be derived. In particular, one or more environmental
sensors associated with a marking device may provide a variety of
environmental information in connection with use of the device;
similarly, one or more operational sensors associated with the marking
device may provide a variety of operational information in connection
with use of the marking device. One or both of such environmental
information and operational information may constitute all or a portion
of marking information and may be employed in any of the manners
described above in connection with marking information. In particular,
environmental information and/or operational information may be
logged/stored in local memory of a marking device, transferred to and
stored in internet accessible memory, formatted in various manners,
processed and/or analyzed at the marking device itself, and/or
transmitted to another device (e.g., a remote computer/server, an
internet storage site, cellular telephone, personal digital assistant
(PDA), etc.) for storage, processing and/or analysis.

[0318]As used herein, environmental sensors are those which sense some
condition of the environment in which the marking device is present, but
need not sense a condition of the marking device itself. Examples of
environmental conditions which may be sensed include, but are not limited
to, temperature, humidity, light, and altitude among others.
Environmental sensors may be included with the marking device for one or
more of various reasons. For example, information provided by one or more
of the environmental sensors may be used to assess whether a marking
operation was or is being performed in suitable environmental conditions
(e.g., within accepted environmental tolerances). Additionally or
alternatively, information provided by one or more environmental sensors
may be used to interact with the technician operating the marking device,
for example by issuing a notification or warning signal to the technician
if the sensed environmental condition is outside of an acceptable range
(i.e., out of tolerance). Also, the information from the environmental
sensor(s) may trigger an action or alteration of the marking device, such
as activating, enabling or disabling a particular component of the
marking device. Additionally or alternatively, information provided by
one or more environmental sensors may augment other information collected
by the marking device, such as any of the types of information described
above as being collected by a marking device according to various
embodiments herein. In some instances, information from two or more of
the environmental sensors may be used in combination, examples of which
are described in detail below.

[0319]As used herein, operational sensors are those which sense some
operating condition of the marking device. Examples of such conditions
include, but are not limited to, the angle of inclination of the marking
device, the direction or heading of the marking device, a pressure
applied to the marking device, and/or some characteristic of motion of
the marking device (e.g., the speed at which the marking device is
moving, the acceleration of the marking device, etc.), among others.
Operational sensors may be included with the marking device for one or
more of various reasons. For example, information provided by one or more
of the operational sensors may be used to assess whether a marking device
was or is operating appropriately during a marking operation or whether
the marking device was or is being operated (e.g., both electronically
and/or physically manipulated) appropriately by the technician (e.g.,
within accepted tolerances or according to protocols). Additionally or
alternatively, information from one or more operational sensors may be
used to detect patterns of operation of the technician, such as
technician "signatures" in using/manipulating the marking device (e.g.,
characteristic movements unique to the technician). Additionally or
alternatively, information from one or more operational sensors may be
used to interact with the technician, for example by issuing a
notification or warning signal to the technician in response to the
detected operational characteristic falling outside of an acceptable
range. Also, the information from the operational sensor(s) may trigger
an action or alteration of the marking device, such as activating,
enabling or disabling a particular component of the marking device.
Additionally or alternatively, information provided by one or more
operational sensors may augment other information collected by the
marking device, such as any of the types of information previously
described herein in connection with other embodiments. Other uses of data
provided by one or more operational sensors are also possible and
contemplated in the various aspects described herein. In some instances,
information from two or more operational sensors may be used in
combination, examples of which are described below. Furthermore,
information from one or more operational sensors may be used in
combination with information from one or more environmental sensors, as
also described further below.

[0320]It should be appreciated that some of the sensors described herein
may be considered both environmental and operational sensors, either
because the sensor senses both an environmental condition and an
operating condition of the marking device (i.e., the sensor senses more
than one condition) or because a single condition sensed by the sensor
may be considered both an environmental condition and an operating
condition. For example, an image capture device may be considered both an
environmental sensor (e.g., the image capture device may capture an image
of the surrounding environment) and an operational sensor (e.g., the
image capture device may capture an image of some action the technician
has taken, such as dispensing of a marker). Furthermore, the operation of
a sensor may change over time. For example, a sensor may be configured at
one time to measure an internal operating temperature and at a different
time to measure an outside ambient temperature. Thus, it should be
appreciated that while the sensors described below are categorized
generally as being either environmental or operational for purposes of
illustrating some exemplary implementations, the categories are not
mutually exclusive, and such categorization is not limiting unless
otherwise stated.

[0321]FIG. 19 is a functional block diagram of a data acquisition system
including a marking device with both environmental sensors and
operational sensors, according to one embodiment of the present
invention. As shown in FIG. 19, the data acquisition system 2000 includes
a marking device 2010 and the previously described remote computer 150.
The marking device 2010 comprises control electronics 112, power source
114, and marking dispenser 116, all of which also have been described
above in connection with other embodiments. The marking device 2010 also
comprises a light source 1832, and one or both of environmental sensors
1820 and operational sensors 1920. It should be appreciated that while
both environmental sensors 1820 and operational sensors 1920 are shown in
the marking device 2010, marking devices according to other embodiments
contemplated by the present disclosure need not necessarily include both
environmental sensors and operational sensors.

[0322]With respect to environmental sensors, non-limiting examples of
suitable environmental sensors include a temperature sensor (e.g., one or
more of an ambient temperature sensor and a surface temperature sensor
(e.g., a temperature sensor for sensing a temperature of a surface on
which marking material is being dispensed)), a humidity sensor, a light
sensor, an altitude sensor, an image capture device (e.g., a camera), and
an audio recorder. This list is not exhaustive, however, as other types
of environmental sensors may be included as appropriate to sense various
environmental conditions of interest.

[0323]FIG. 20 is a block diagram showing details of the environmental
sensors 1820 shown in FIG. 19, according to one embodiment of the present
invention. In FIG. 20, the illustrated environmental sensors 1820 include
an ambient temperature sensor 1822, a surface temperature sensor 1823, a
humidity sensor 1824, a light sensor 1826, an altitude sensor 1827, an
image capture device 1828, and an audio recorder 1830. Additional or
alternative environmental sensors may be included, and one or more of the
illustrated environmental sensors may be omitted, in some embodiments.
The environmental sensors may be coupled to the processor 118 to receive
control signals from the processor 118 and/or to provide their respective
outputs (e.g., signals, data, information) to the processor 118, and, as
described further below, may operate in one of various suitable manners.
Information provided by any of the environmental sensors may be stored in
local memory 122, for example as an electronic record 2835, described
below, and/or transmitted to an external device, such as the remote
computer 150, remote storage, etc.

[0324]The ambient temperature sensor 1822 may be configured to sense the
ambient temperature in the vicinity of the marking device 2010. The
ambient temperature may be a useful piece of information, for example in
determining whether the temperature is adverse to performance of the
marking operation, which may occur when the temperature is too hot or too
cold (e.g., thereby adversely affecting some characteristic of the
marking material itself, or dispensing of marking material). For example,
in some embodiments, it may be preferable to operate the marking device
only within a predetermined ambient temperature range between 20°
F. and 110° F., although other ranges are possible. In addition,
as described further below, the ambient temperature may be useful in
combination with one or more other types of environmentally sensed
inputs, such as humidity, in evaluating the conditions in which a marking
operation is performed.

[0325]The ambient temperature sensor may be any suitable temperature
sensor, such as an infrared sensor, and may be an analog or digital
temperature sensor, as the various aspects described herein relating to a
marking device including an ambient temperature sensor are not limited to
using any particular type of temperature sensor. According to one
embodiment, the temperature sensor may be part of a combined temperature
and humidity sensor, such as the HS-2000V from Precon of Memphis, Tenn.
In some embodiments, the ambient temperature sensor may be suitable to
operate between -40° F. and 125° F., or over any other
suitable range, which in some embodiments may encompass the expected
temperatures to which the marking device may be exposed during normal
operation. The data output by the ambient temperature sensor 1822 may be
stored in local memory 122 and/or may be transmitted to an external
device, such as remote computer 150, in those embodiments in which the
marking device 2010 is communicatively coupled to the external device.

[0326]The surface temperature sensor 1823 may be configured to sense the
temperature of the surface on which the marking device is dispensing the
marking material (e.g., the ground under the marking device). The
temperature of the surface may be useful information for various reasons,
for example in assessing whether the surface temperature is within an
acceptable range for dispensing the marking material. As an example, some
commercially available paints, which may be used as a marking material in
some embodiments, provide recommended temperature ranges for painting,
such as between 70° F. and 80° F., outside of which the
paint may not coat, sufficiently dry or remain on the painted surface.
Thus, as a non-limiting example, information from the surface temperature
sensor 1823 may be used to assess whether the marking operation was or is
being performed in such recommended temperature conditions. As with the
ambient temperature sensor 1822, the information provided by the surface
temperature sensor 1823 may be stored in local memory 122 and/or
transmitted to an external device, such as the remote computer 150.

[0327]The surface temperature sensor 1823 may be any suitable type of
sensor for determining surface temperature, such as an infrared
temperature sensor or any other suitable type of temperature sensor. In
some embodiments, the surface temperature sensor may be configured to
operate across a range of temperatures encompassing all expected surface
temperatures on which marking material may be dispensed during normal
operation. For example, in one embodiment the surface temperature sensor
may operate between -40° F. and 125° F., although other
temperature ranges are also possible.

[0328]The humidity sensor 1824 may be configured to sense the humidity of
the environment in which the marking device 2010 is used, and in some
embodiments may provide a relative humidity measurement (e.g., 0% to 100%
humidity). Such information may be useful alone or in combination with
other information in determining whether, for example, the environment is
too humid for performance of the marking operation. For example, if the
humidity is too great, marking material such as paint may not adequately
dry and/or remain in place on the surface on which it is dispensed. In
some embodiments, humidity greater than 90% may be adverse to painting,
although the humidity tolerance may differ for different materials. Thus,
an acceptable humidity for painting on grass, for example, may differ
from that for painting on concrete or dirt. The humidity information
provided by humidity sensor 1824 may be used to assess whether a marking
operation was or is being performed within acceptable humidity
tolerances. The humidity sensor may be any suitable type of humidity
sensor, as the type is not limiting. According to one embodiment, the
humidity sensor may be part of a combined temperature and humidity
sensor, such as the HS-2000V from Precon of Memphis, Tenn. The
information provided by the humidity sensor 1824 may be stored in local
memory 122 and/or transmitted to an external device, such as the remote
computer 150.

[0329]The light sensor 1826 may be configured to sense the intensity,
flux, or illuminance of ambient light in the vicinity of the marking
device 2010. Such information may be useful, for example, to assess
whether a marking operation was or is being performed in suitable
lighting conditions (e.g., whether there was sufficient light to allow
for accurate performance of a marking operation, whether the area
surrounding the marking operation is sufficiently lit to ensure worker
safety, etc.). The light sensor 1826 may be any suitable type of light
sensor. In one embodiment, the light sensor is a cadmium sulfide (CdS)
photocell, which is a photoresistor device whose resistance decreases
with increasing incident light intensity. Such a device may provide a
resistance or voltage measurement as its output indicative of measured
flux. However, other types of light sensors may alternatively be used.
One non-limiting example of a suitable photocell is the PDV-P5001 from
Advanced Photonix, Inc. of Ann Arbor, Mich.

[0330]The units output by the light sensor may depend on whether the light
sensor is sensing light intensity, light flux, or illuminance. For
example, the output may be in candela for light intensity, lumen for
flux, or lux for illuminance. According to one embodiment, target values
for illuminance for accurate performance of a marking operation may be
between approximately 1,000 lux and 100,000 lux, although other ranges
may be appropriate based on a particular location and type of marking
operation being performed. According to one embodiment, the output may be
converted to a percentage between 0% and 100%, for example in which 0%
corresponds to darkness and 100% corresponds to full sunlight. Other
outputs may alternatively be produced. The information provided by the
light sensor 1826 may be stored in local memory 122 and/or transmitted to
an external device, such as the remote computer 150.

[0331]According to one embodiment, the marking device further comprises a
light source 1832, such as a flashlight or light emitting diode (LED)
torch. The light source 1832 may be activated manually (e.g., by the
technician) or may be coupled to the light sensor 1826 (e.g., directly
coupled or coupled through one or more components, such as processor 118)
and activated automatically in response to the light sensor sensing an
unsatisfactorily low lighting condition (e.g., by receiving a signal from
processor 118 or by directly receiving an output signal of the light
sensor). The threshold light level for such automatic activation may be
any suitable level, non-limiting examples of which include any level at
which the technician may have difficulty seeing and therefore performing
the marking operation, and any predetermined level below which technician
safety may be comprised. Information about such activation of the light
source (e.g., the occurrence of the activation, the time of activation,
the duration, etc.) may be stored in local memory 122 and/or transmitted
to an external device, such as the remote computer 150.

[0332]The altitude sensor 1827 may be configured to measure the altitude
of the marking device 2010, and may be any suitable type of altitude
sensor for doing so. The altitude at which a marking operation is
performed may impact the performance of a marking material (e.g., paint)
and worker safety, among other considerations. Thus, information about
the altitude may be useful for a variety of reasons.

[0333]The output of the altitude sensor 1827 may be in any suitable units,
and in some embodiments provides an altitude with respect to sea level.
For example, the altitude sensor may provide an altitude in meters,
miles, feet, or any other suitable units. The information provided by the
altitude sensor 1827 may be stored in local memory 122 and/or transmitted
to an external device, such as the remote computer 150.

[0334]The image capture device 1828 may be positioned on the marking
device to capture an image of the environment surrounding the marking
device 2010, may be positioned to capture an image of marking material
dispensed by the marking device 2010, or may be configured or
configurable in any suitable manner to capture any type of image of
interest. According to one embodiment, a technician may be meant to take
a picture of the marking material dispensed during a marking operation
and/or of an environmental landmark in the vicinity of where marking
material is dispensed. Thus, inclusion of an image capture device 1828 in
the marking device 2010 may facilitate compliance with such protocols.

[0335]The image capture device 1828 may be capable of taking still images,
video images, or both, as the various aspects described herein relating
to marking devices including an image capture device are not limited in
this respect. Thus, the image capture device 1828 may be any suitable
type of image capture device, and in some embodiments may be a type that
is suitable for use in a portable device, such as, but not limited to,
the types of digital cameras that may be installed in portable phones,
wide angle digital cameras, 360 degree digital cameras, infrared (IR)
cameras, and the like. In some implementations, a wide angle lens and
automatic zoom may be utilized to maximize the coverage area of each
image.

[0336]The output of the image capture device may include various
information. The output may include all or part of a captured image.
Additionally or alternatively, the output may include information about
the settings and/or operation of the image capture device, such as any
one or more of resolution, frame rate (for video images), flash status
(i.e., flash used or not used), image size, video sequence duration, zoom
setting, etc.

[0337]In those embodiments in which the image capture device is a digital
device, the images may be stored in local memory 122 and/or transmitted
to an external device, such as the remote computer 150. The images may be
in any standard or proprietary image file format (e.g., JPEG, TIFF, BMP,
etc.). Furthermore, the images may be associated with a specific job, a
geographic position, and an exact time, in some embodiments, for example
by flagging the image based on the time at which it was taken, the
location at which it was taken, and/or the job during which it was taken.
In one embodiment, each captured image may be cached and transmitted with
all other captured data from one or more other sensors/input devices.

[0338]The environmental sensors 1820 may further comprise an audio
recorder 1830, which may be used to capture audio input from a technician
and/or from the environment (e.g., sounds in the vicinity of the marking
device). Thus, in one embodiment, the technician may, for example,
dictate notes relating to the performance of the marking operation, such
as describing visible landmarks in the area of the marking operation,
notes about performance of the marking device, or any other notes which
may be relevant to performance of a marking operation. In one embodiment,
the audio recorder may record sounds from the environment, such as
passing cars, planes, etc. Such recordings may be useful, for example, in
assessing whether a technician was at the intended location of the
marking operation. For example, if a passing train is evident from the
recording and the intended marking location is not near a train track,
the recording may provide evidence that the technician was in the wrong
location.

[0339]The audio recorder 1830 may be an analog or digital device or
devices. For example, in one embodiment the audio recorder 1830 may be an
analog recorder configured to receive an analog input signal (e.g., from
a microphone) and store the analog signal. According to another
embodiment, the audio recorder 1830 may be a digital audio recorder,
including any suitable combination of components for receiving an analog
signal (e.g., from a microphone), converting the analog signal to a
digital signal, performing any suitable digital signal processing (e.g.,
filtering, amplifying, converting to text, etc.) and storing the digital
information. According to one embodiment, the audio recorder may include
a dedicated digital audio processor to perform those functions recited or
any other suitable functions. It should be appreciated from the foregoing
that a microphone (not shown in FIG. 19) may be associated with the audio
recorder 1830 to provide the audio input to the audio recorder.

[0340]According to one embodiment, for example in which a technician may
dictate notes, the audio processing of the audio input may include
performing speech recognition (e.g., speech to text generation). Such
functionality may be provided by suitable speech recognition software
executing on a dedicated audio processor, or in any other suitable
manner. Any generated text may be, for example, displayed on a display of
the user interface 126, or may be stored for later display on a separate
device.

[0341]The recordings provided by the audio recorder 1830 may be stored in
a dedicated audio memory, in local memory 122 and/or transmitted to an
external device, such as the remote computer 150. In those embodiments in
which the audio recorder is a digital audio recorder, the audio files may
be in any standard or proprietary audio file format (e.g., WAV, MP3,
etc.).

[0342]Although not illustrated in FIG. 20, the communication interface 124
of FIG. 19 may also serve as or enable another environmental sensor.
According to one embodiment, the marking device may be internet enabled
and information may be received via the communication interface 124 over
the internet. According to one embodiment, information about an
environmental condition may be received via the communication interface.
For example, temperature information or humidity information, among
others, may be received over the internet via communication interface
124. In such instances, the received temperature or humidity information
may augment any temperature and humidity information collected by a
temperature and humidity sensor of the marking device, or may replace
such information, such that in some embodiments the marking device may
not include a physical temperature or humidity sensor. Thus, it should be
appreciated that the communication interface may serve as a "virtual
sensor" by receiving environmental information of interest, not being
limited to temperature and humidity.

[0343]As explained above, another type of input device which may be
included with a marking device is an operational sensor. Thus, according
to one aspect of the present invention and as shown in FIG. 19, the
marking device 2010 may include one or more operational sensors 1920 for
sensing one or more operating conditions or characteristics of the
marking device.

[0344]FIG. 21 is a block diagram showing details of the operational
sensors shown in FIG. 19, according to one embodiment of the present
invention. The illustrated exemplary operational sensors 1920 include,
but are not limited to, one or more temperature sensors 1922, a compass
1924, an inclinometer 1926, one or more accelerometers 1928, a yaw rate
sensor 1929, a proximity sensor 1930, a pressure sensor 1931, one or more
device health sensors 1932, the image capture device 1828, and the audio
recorder 1830. Additional or alternative operational sensors may be
included, and one or more of the illustrated operational sensors may be
omitted, in some embodiments. The operational sensors may be coupled to
the processor 118 to receive control signals from the processor 118
and/or to provide their respective outputs to the processor 118, and, as
described further below, may operate in one of various suitable manners.
Information provided by any of the operational sensors may be stored in
local memory 122, for example in an electronic record 2835, described
below, and/or transmitted to an external device, such as the remote
computer 150, remote storage, etc.

[0345]One or more operational temperature sensors 1922 may be configured
to sense any temperature of interest with respect to the marking device
2010. For example, it may be desirable in some embodiments to monitor the
temperature of the processing circuitry of the marking device 2010, such
as the temperature of the processor 118. Alternatively, it may be
desirable in some embodiments to monitor the temperature of other
components of the marking device 2010, for example, the temperature of
one of the other operational sensors 1920. Thus, it should be appreciated
that a plurality of operational temperature sensors 1922 may be included
and arranged to sense any operating temperatures of interest of the
marking device 2010. In this manner, the operating temperatures of one or
more components of the marking device 2010 may be monitored and an alert
or notification may be generated (e.g., by the control electronics) and
provided to the technician if one of the operating temperatures is
determined to be outside of an acceptable tolerance, for example if a
component is overheating. Alternatively, the temperature from one or more
operational temperature sensors 1922 may be used to calibrate or
compensate data or signals provided by any one of the other sensors which
may have a temperature-dependent output.

[0346]The temperature sensor(s) 1922 may be any suitable temperature
sensor, such as a temperature-dependent variable resistor, or any other
type of temperature sensor suitable for measuring the temperature of the
components of interest of the marking device. The temperature sensor 1922
may be configured to operate over any suitable temperature range of
interest, which in one embodiment may be from -40° F. to
125° F., although other temperature ranges may be employed in
other embodiments. The data output by the temperature sensor 1922 may be
stored in local memory 122 and/or may be transmitted to an external
device, such as remote computer 150, in those embodiments in which the
marking device 2010 is communicatively coupled to the external device.

[0347]The compass 1924 may be configured to determine the direction in
which the marking device 2010 is facing, and therefore may be positioned
at one of various suitable locations. For example, according to one
embodiment, the compass 1924 may be positioned toward the top of the
marking device 2010, and aligned such that the compass identifies the
direction toward which the front of the marking device points (i.e., the
direction in which the marking device faces when held by the technician).
The heading information provided by the compass 1924 may be provided in
degrees or in any other suitable units, and may be provided relative to a
reference direction (e.g., relative to true North). According to one
embodiment, the compass may be initially calibrated to true North, such
that subsequent heading readings may be relative to true North.

[0348]The heading information provided by the compass 1924 may be useful
to determine a direction in which the technician moves during a marking
operation. Such information may be particularly useful in instances in
which the location tracking system 130 does not provide a signal or a
sufficiently accurate signal to monitor the technician's movements. The
compass 1924 may be any suitable type of compass, including analog or
digital, and may provide any suitable readout. According to one
embodiment, the compass 1924 is a digital compass, which provides a
heading of the marking device 2010. According to one embodiment, the
compass may include one or more gyroscopes. According to one embodiment,
the compass 1924 is an OS4000-T solid state tilt compensated nano compass
available from OceanServer Technology, Inc. of Fall River, Mass. The
information provided by the compass 1924 may be stored in local memory
122 and/or transmitted to an external device, such as the remote computer
150.

[0349]The inclinometer 1926 may be any suitable inclinometer configurable
to measure an angle of inclination of the marking device 2010. According
to one embodiment, the inclinometer may provide an angle with respect to
ground. According to one embodiment, the inclinometer may be a multi-axis
digital device and may sense angles with respect to horizontal and/or
vertical planes. The inclinometer may provide a voltage as an output
signal, indicative of the angle of inclination. According to some
embodiments, the inclinometer may have an output range spanning+/-30
degrees (e.g., with respect to ground), although other ranges may
alternatively be provided by some inclinometers.

[0350]The inclinometer 1926 may be positioned toward the top of the
marking device 2010, for example, near where the technician may hold the
marking device during use. Alternatively, according to another
embodiment, the inclinometer may be positioned substantially near the tip
of the marking device 2010 (i.e., the end of the marking device from
which marking material is dispensed), which may be substantially the same
as tip 2302 of the marking device 2100 illustrated in FIG. 23. Other
locations for the inclinometer with respect to the marking device are
also possible.

[0351]The information provided by the inclinometer may be useful for one
or more of various purposes. For example, according to one embodiment,
the information about the angle of the marking device may be useful in
determining whether the technician is appropriately using the marking
device (e.g., for determining whether the marking device is being held at
a suitable angle relative to the surface (e.g., the ground) on which
marking material is being dispensed to ensure accurate dispensing of the
marking material), and in some instances may therefore be used to disable
the marking dispenser if the technician is holding the marking device at
an inappropriate angle. According to another embodiment, as described in
further detail below in connection with FIG. 28, the information about
the angle of the marking device may be used to determine the location of
one point of the marking device relative to a second point of the marking
device (e.g., for use in determining the relative positioning of the tip
of the marking device compared to the top of the marking device). The
information provided by the inclinometer may be stored in local memory
122 and/or transmitted to an external device, such as the remote computer
150.

[0352]One or more accelerometers 1928 may be configured to sense the
acceleration of the marking device 2010 and may provide an output in
terms of g-force or in any other suitable units. Such information may be
useful, for example, in assessing whether a technician is appropriately
using (e.g., physically moving or manipulating) the marking device 2010.
For example, there may be predetermined acceptable acceleration ranges
associated with normal operation of the marking device, and therefore the
accelerometer(s) 1928 may provide information which may be used to assess
whether a technician is operating the marking device 2010 within those
acceptable ranges. In addition, any acceleration data provided by the
accelerometer(s) may be integrated to obtain velocity data and/or
integrated twice to obtain data about distance traveled (e.g., via
appropriate functionality included in the marking data algorithm 134 or
other algorithm executed by the processor 118), either of which
integration results may be useful for a variety of reasons. The
acceleration information provided by the accelerometer(s) 1928 may be
stored in local memory 122 and/or transmitted to an external device, such
as the remote computer 150.

[0353]The accelerometer(s) 1928 may be any suitable accelerometer for
sensing the acceleration of the marking device and may provide any
suitable outputs. According to one embodiment, the accelerometer may be a
3-axis accelerometer, providing an indication of the acceleration of the
marking device along three orthogonal axes. The output of each axis may
be a frequency (e.g., in Hz) or may be converted to units of g. For
example, in one embodiment the accelerometer may be a 3-axis
accelerometer that outputs a signal ranging from 0.5 Hz-550 Hz for the
z-axis, from 0.5 Hz-1600 Hz for the x-axis, and from 0.5 Hz-1600 Hz for
the y-axis. Again, the accelerometer may alternatively provide an output
in terms of g or any other suitable units. In one exemplary
implementation, an accelerometer may be an ADXL 330KCPZ-RL accelerometer
available from Analog Devices of Norwood, Mass. In some exemplary
implementations, the accelerometer may output acceleration data, whereas
in other implementations the accelerometer may output velocity data along
each of the three axes, as well as the orientation of the accelerometer.

[0354]In addition to providing acceleration data, an accelerometer may be
operated as an inclinometer according to known techniques (see, e.g.,
description at
http://www.tilt-china.com/uploadPDF/How_to_use_an_accelerometer_as_an_inc-
linometer.pdf, viewed on Jan. 27, 2010 and prepared by Shanghai Vigor
Technology Development Co.). Thus, according to one embodiment of the
present invention, a marking device may include an accelerometer
configured to function as an inclinometer and therefore provide a measure
of inclination of the marking device.

[0355]Furthermore, as explained in greater detail below, the marking
device 2010 may comprise a plurality of accelerometers located at
different positions with respect to the marking device. Information from
such accelerometers may be useful, for example, in assessing the relative
motion of one portion (e.g., the tip) of the marking device with respect
to a second portion (e.g., the top) of the marking device, for example
using the techniques described in U.S. Patent Application Publication
2008/0255795, which is hereby incorporated herein by reference in its
entirety. According to one such non-limiting embodiment, one
accelerometer may be positioned near the tip of the marking device and a
second accelerometer may be positioned near the top of the marking
device. Both may be 3-axis accelerometers. Such an arrangement may also
be used to determine the location of the tip of the marking device
relative to the location of the top of the marking device, as explained
below in connection with FIG. 28.

[0356]Additionally, the data output by one or both accelerometers may be
used to monitor for out-of-tolerance operation of the marking device,
such as improper manipulation of the marking device by the technician.
For example, acceleration data from either accelerometer may be
indicative of whether the marking device is being swung, thrown, or
dropped, among other things. For example, acceleration values from either
accelerometer above some threshold value for a sufficient duration (e.g.,
for one second or greater, or any other suitable duration) may be
indicative of the marking device being thrown or dropped. The threshold
value of acceleration indicative of such behavior may be different for
the two accelerometers. Similarly, detection of acceleration values
deviating from an expected or target pattern may be indicative of misuse
of the marking device. In response to detecting such manipulation of the
marking device, various actions may be taken, such as generating an
alert, logging an event, disabling the actuation system of the marking
device, or any of the actions described further below.

[0357]Moreover, a marking device may be provided with two accelerometers
to monitor whether the marking device is being held in a satisfactory
manner during use. For example, it may be preferable for a marking device
to be maintained at a substantially perpendicular angle relative to
ground as a technician is painting, even when the technician is moving
(e.g., swinging) the marking device. It should be appreciated that when
operated in a such a manner, the top of the marking device and the tip of
the marking device may exhibit similar acceleration characteristics
(e.g., peaks in acceleration at the same time (e.g., at the same points
of a swinging motion), minimum values of acceleration at the same time
(e.g., at the same points of a swinging motion), etc.) By positioning an
accelerometer toward the tip of the marking device and another toward the
top of the marking device, the resulting acceleration data may be
indicative of whether the technician is properly manipulating the marking
device.

[0358]Other uses for multiple accelerometers on a marking device are also
possible, and those examples listed above are non-limiting.

[0359]The operational sensors 1920 may further comprise a yaw rate sensor
1929, which may be configured to sense the yaw rate (i.e., a twisting
motion) of the marking device. The yaw rate sensor may be any suitable
yaw rate sensor and may provide its output in any suitable units, for
example in degrees per second (degrees/sec). One non-limiting example of
a suitable yaw rate sensor is an ADXRS610BBGZ-RL gyro sensor from Analog
Devices of Norwood, Mass. According to another embodiment, a yaw rate
measurement may be provided by some types of compasses, such that a
combination compass and yaw rate sensor may be used. The yaw rate sensor
may be positioned at any suitable location on the marking device to
detect yaw rate. The information provided by the yaw rate sensor 1929 may
be stored locally and/or transmitted to an external device such as the
remote computer 150.

[0360]The proximity sensor 1930 may be configured to measure the distance
from any point of interest of the marking device 2010 to a point of
interest in its surroundings. For example, in one embodiment, the
proximity sensor 1930 may be positioned at the tip of the marking device,
and may be oriented to determine the distance between the tip of the
marking device and any surface upon which marking material is being
dispensed by the marking device (a target surface). Alternatively, in one
embodiment, the proximity sensor may be positioned toward the top of the
marking device and oriented to determine a distance between the top of
the marking device and the ground. Other configurations are also
possible.

[0361]Information about the distance from the marking device to any
surrounding surface may be useful for one of various reasons. For
example, such information may be useful in assessing whether a technician
is properly operating the marking device. As a non-limiting example,
there may be predetermined acceptable distances between the marking
dispenser of the marking device and the surface on which marking material
is being dispensed. Some spray paint cans, for example, are provided with
instructions giving recommended distances (e.g., between 6-12 inches)
between the paint can and the surface to be painted. The proximity sensor
may be used to determine whether the technician is maintaining the
marking device at an acceptable distance from the surface upon which the
marking material is being dispensed. Alternatively, according to another
embodiment, and as described in greater detail below, the distance of a
portion of the marking device from the ground may be useful in
determining the distance between two points of the marking device.

[0362]The proximity sensor 1930 may be any suitable type of proximity
sensor (e.g., any commercially available proximity sensor), including an
analog or digital device. In one embodiment, proximity sensor 1930 may be
a Sharp GP2D120 short range IR distance sensor from Sharp Electronics
Corporation (Mahwah, N.J.) and is able to take a substantially continuous
distance reading and return a corresponding analog voltage with a range
of about 1.6 inches to about 12 inches. Such a proximity sensor may be
suitable, for example, when the sensor is used to sense the distance from
the tip of the marking device to a surface on which marking material is
being dispensed, since such a distance may typically be less than about
12 inches. According to another embodiment, the proximity sensor may be a
sonar device. Other types of proximity sensors may also be suitably used.
The information provided by the proximity sensor 1930 (e.g., a distance
value, for example, in centimeters, meters, or feet) may be stored
locally and/or transmitted to an external device such as the remote
computer 150.

[0363]The pressure sensor 1931 may be configured to sense any pressure of
interest with respect to the marking device. For example, according to
one embodiment it may be desirable to detect the pressure applied to a
handle of the marking device, for instance to determine whether a
technician is holding the marking device and, if so, whether it is being
held appropriately. Accordingly, a pressure sensor may be positioned in
the handle of the marking device in one non-limiting embodiment and
configured to detect the pressure applied to the handle. According to
another embodiment, it may be desirable to determine the pressure applied
to an actuation system of the marking device, for example if the
actuation system is a trigger. Accordingly, a pressure sensor may be
configured to determine the pressure applied to the trigger or other
actuation mechanism in those embodiments in which the marking device
includes such a trigger or actuation mechanism. According to one
embodiment, the marking device may include multiple pressure sensors, for
example one for determining the pressure applied to a handle of the
marking device and one for determining a pressure applied to an actuation
system of the marking device. However, any number of pressure sensors may
be included, and they may be configured to sense any pressure of interest
with respect to the marking device.

[0364]The pressure sensor 1931 may be any suitable type of pressure sensor
for detecting the pressure of interest. The information provided by the
pressure sensor 1931, which may be in any suitable units, may be stored
locally and/or transmitted to an external device such as the remote
computer 150.

[0365]The marking device may further include device health monitoring
capability. Characteristics of the health of the marking device which may
be the subject of monitoring include, but are not limited to, battery
life, battery drain level, battery charging capacity, wireless signal
strength (in those embodiments in which the marking device has wireless
capabilities), network connectivity, operating temperature, available
memory, and the status of any one or more input devices of the marking
device, such as an accelerometer, location tracking system (e.g., GPS
receiver), image capture device, light sensor, marking material detection
mechanism, etc. To this end, the marking device may include hardware
and/or software configured to serve the health monitoring purpose.

[0366]According to one embodiment, the marking device may include a
processor (e.g., processor 118) configured to run a device health
software program or application to process the inputs from one or more
operational sensors, such as operational temperature sensor 1922, to
assess whether those inputs indicate the marking device is operating
appropriately. According to another embodiment, the marking device may
include dedicated device health hardware, such as device health sensor
1932, which may provide data that is processed by a device health
software program (for example, executing on processor 118) to assess the
health of the marking device. Non-limiting examples of device health
sensor 1932 include a voltmeter and an ammeter, among others.

[0367]In one embodiment, data provided by the device health sensor 1932
may indicate that a low battery condition is present during the marking
operation and, thus, it may be determined that the operations of the
marking device are not reliable. Other device conditions, such as
wireless signal strength (e.g., in those embodiments in which the marking
device 2010 is wirelessly coupled to an external device, such as remote
computer 150), available memory, temperature of one or more components of
the marking device, power connection of one or more components of the
marking device, or other conditions of the marking device may be
monitored by a device health sensor. Thus, it should be appreciated that
a marking device according to the embodiments described herein may
include any suitable number of device health sensors for monitoring a
desired number of device conditions.

[0368]According to one embodiment, a record or message may be created
based on operation of the device health sensor. For example, a record or
message may be created including a device ID (e.g., of the marking
device) and the current state of certain device components, such as input
devices (e.g., environmental and operational sensors). The record or
message may also or alternatively include an identification of any
resource utilization that is nearing a specified threshold (e.g., memory
nearing capacity). Thus, it should be appreciated that various conditions
may be monitored under the rubric of monitoring the health of the marking
device, and various actions taken in response to such monitoring.

[0369]The operational sensors 1920 may further comprise the image capture
device 1828. As previously mentioned, the image capture device 1828 may
be considered an operational sensor, for example, if and when configured
to capture an image relating to the operation of the marking device 2010.
In one embodiment, the image capture device may be configured to capture
an image of any marking material dispensed by the marking device 2010.
Such an image may be used to verify that a marking material was
appropriately placed on ground, pavement or other surface in the context
of its surroundings. Images of dispensed marking material such as a paint
also may be used to verify that the marking material appropriately coated
and adhered to a surface on which it was dispensed. Images of marking
material as it is being dispensed also may be used to ascertain and/or
verify some attribute or characteristic of the marking material itself.
Concepts relating to determination of various marking material attributes
using a variety of techniques are discussed in U.S. Non-provisional
application Ser. No. 12/429,947, filed Apr. 24, 2009, and entitled
"MARKER DETECTION MECHANISMS FOR USE IN MARKING DEVICES AND METHODS OF
USING SAME," published as U.S. Patent Publication 2010-0006667-A1, which
application is hereby incorporated by reference.

[0370]Furthermore, the operational sensors 1920 may comprise an audio
recorder, similar to or the same as audio recorder 1830, and therefore
shown as audio recorder 1830 in FIG. 21. For example, the marking device
may include multiple audio recorders, with one or more operating as an
environmental sensor (e.g., recording acoustic input from the
environment) and one or more operating as operational sensors (e.g.,
recording acoustic input relating to operation of one or more components
of the marking device, as described below with respect to the marking
dispenser). According to one non-limiting embodiment, an audio recorder
may be configured to record audio input corresponding to the sound
created by dispensing of marking material from the marking dispenser 116.
For example, in one embodiment, the marking dispenser 116 may comprise an
aerosol paint can and the marking material may be the paint. A sound is
often emitted when the aerosol paint can is activated. The frequency of
that sound may depend on, and therefore be indicative of, what is being
dispensed from the paint can. For example, in one embodiment the paint
can may have a fixed resonance frequency with resonance sidebands. The
frequency of the resonance sidebands may vary depending on the amount of
paint in the paint can, such that the resonance sidebands may move closer
(in terms of frequency) to the fixed resonance frequency as the amount of
paint in the paint can decreases. Thus, by suitable detection of the
resonance sidebands during actuation of the paint can, a determination
may be made whether paint is being dispensed or not. Also, if no paint or
propellant is being dispensed from the paint can (e.g., when the paint
can is empty of both paint and propellant or if the paint can is not
functioning), then no sound may be emitted. A non-limiting example is now
given.

[0371]According to one embodiment, the frequency amplitude of the sound
generated by the paint can may be tracked over time to assess an amount
of paint in the paint can and/or whether paint is being dispensed. If the
amplitude of a particular frequency of interest remains above a threshold
value for a threshold duration, it may be determined that paint is being
dispensed. By contrast, if the amplitude of the frequency of interest
does not remain above the threshold value for the threshold duration, it
may be determined that the paint can is not dispensing paint, e.g.,
because the paint can is substantially empty of paint or is not
functioning.

[0372]According to one embodiment, a method of determining whether paint
is being emitted from a marking dispenser may begin by calibrating the
audio recorder to account for background noise, although not all
embodiments involve such a calibration routine. A microphone associated
with the audio recorder is positioned to detect sound emitted when a
paint can, serving as the marking dispenser 116 in this non-limiting
embodiment, is activated. Thus, according to one embodiment, the
microphone may be positioned proximate the tip of the marking device, an
example of which is shown later in FIG. 23 (which illustrates a
microphone near the tip 2302 of the marking device 2100). The analog
signal from the microphone may be digitized by sampling at 20 kHz or any
other suitable sampling rate. The digital data may then be low-pass
filtered, for example by a processor (e.g., processor 2118, described
below). According to one embodiment, the low-pass filter has a passband
at approximately 3.3 kHz, although any suitable passband may be used. The
data from the low-pass filter may then be squared in value, which removes
any negative values. The resulting data may then be low-pass filtered,
for example using the same processor which performed the first low-pass
filtering function, or any other suitable hardware and/or software. This
second low-pass filtering step may have a passband at approximately 50
Hz, although any suitable passband may be used.

[0373]The amplitude of the signal output by the second low-pass filtering
step may then be compared against a threshold amplitude selected to be
indicative of the amount of paint in the paint can and/or being
dispensed. If the amplitude exceeds the threshold amplitude for a
sufficient duration (e.g., 50 milliseconds, 25 milliseconds, or any other
suitable duration), then the data suggests that the paint can contains
paint, since such a result may occur when the resonance frequency
sidebands of the paint can are sufficiently far from the fixed resonance
frequency. By contrast, if the amplitude does not exceed the threshold
amplitude for the threshold duration, then the data suggests that the
paint can contains little or no paint. The threshold amplitude may be
selected based on characteristics of the subject paint can, among other
things.

[0374]It should be appreciated that other methods of processing the audio
input are also possible, as this is only one example. In addition, other
uses of the audio recorder information (i.e., other than determining if
marking material has been dispensed) are possible. Furthermore, it should
be appreciated that the audio input may also be stored by the audio
recorder.

[0375]As previously described, the audio recorder may be any suitable
audio recorder, including a digital audio recorder or analog audio
recorder, for example of any of the types previously described. In one
embodiment, the audio recorder may comprise a dedicated PIC processor, as
described further below with respect to FIG. 22. In those embodiments in
which the marking device includes two or more audio recorders (e.g., one
operating as an environmental sensor and another operating as an
operational sensor), the audio recorders may share any suitable
combination of circuitry. For example, multiple audio recorders may share
a same digital signal processor (e.g., a dedicated audio signal
processor). A separate microphone may be associated with each audio
recorder, or a microphone may be shared between two or more audio
recorders. Thus, it should be appreciated that the exact configuration
and components of audio recorders according to the various embodiments
described herein are not limiting.

[0376]The audio files produced by an audio recorder operating as an
operational sensor may be stored locally in dedicated audio memory, in
local memory 122 and/or transmitted to an external device, such as the
remote computer 150.

[0377]In any of the embodiments illustrated in FIG. 19, any one or more of
the environmental sensors 1820 illustrated in FIG. 20 and/or operational
sensors 1920 illustrated in FIG. 21 may be operated in any suitable
manner, including continuously, periodically, and/or in response to an
event or trigger (e.g., one or more actuations of the marking device), or
in any other suitable manner. For example, one or more of the
environmental sensors 1820 and/or operational sensors 1920 may operate
continuously during performance of a marking operation. In particular,
the ambient temperature sensor may output a substantially continuous data
stream indicative of the sensed ambient temperature. Similarly, the
surface temperature sensor, humidity sensor, light sensor, and altitude
sensor may output substantially continuous data streams indicative of the
respective sensed conditions. The inclinometer, compass, accelerometer,
yaw rate sensor, proximity sensor, pressure sensor, and device health
sensor may also output substantially continuous data streams indicative
of the sensed operation. The image capture device 1828 may record a video
sequence continuously during the marking operation, and the audio
recorder 1830 may continuously record any audio input during performance
of the marking operation.

[0378]Alternatively, one or more of the environmental sensors 1820 and/or
operational sensors 1920 may be operated and/or polled periodically, with
the resulting output data being logged and/or transmitted periodically.
For example, the ambient temperature sensor may provide an output signal
indicative of the sensed ambient temperature every second, every five
seconds, every ten seconds, every minute, every ten minutes, or at any
other suitable time interval. Similarly, the surface temperature sensor,
humidity sensor, light sensor, altitude sensor, operational temperature
sensor(s), inclinometer, compass, accelerometer(s), yaw rate sensor,
proximity sensor, pressure sensor, and device health sensor(s) may output
data at periodic intervals. The image capture device may capture a still
image or a video sequence of any desired duration at periodic intervals.
The audio recorder may capture audio of any desired duration at periodic
intervals. It should be appreciated that in some embodiments one or more
of the environmental sensors 1820 and/or operational sensors 1920 may
themselves operate so as to provide output information in an essentially
continuous fashion, but only be read or polled (e.g., by processor 118)
on some discrete or periodic basis. Accordingly, output signals or data
provided by one or more sensors may be acquired, logged into local
memory, and/or transmitted to an external device in any of a variety of
manners.

[0379]According to another embodiment, one or more of the environmental
sensors 1820 and/or operational sensors 1920 may operate, be read
discretely, and/or be polled, and therefore the corresponding data may be
logged and/or transmitted, in response to actuation of the actuation
system 120 of the marking device. For example, actuation of the actuation
system 120 may trigger dispensing of marking material and simultaneously
may trigger recording of a sensed ambient temperature from ambient
temperature sensor 1822 in the local memory 122. The remaining
environmental sensors 1820 and/or operational sensors 1920 may be
operated, read and/or polled in a similar manner.

[0380]In one embodiment, one or more of the environmental sensors 1820
and/or operational sensors 1920 may be activated, read discretely, and/or
polled by the technician irrespective of whether the actuation system 120
is actuated. For example, the technician may activate, read, and/or poll
one or more of the environmental sensors by depressing a selection button
corresponding to the environmental sensor(s), by choosing a selection
button or menu option from a user interface of the marking device (in
those embodiments in which the marking device includes a user interface),
or in any other suitable manner. The operational sensors may operate
similarly.

[0381]Thus, it should be appreciated that the operation of sensors, and
reading and/or logging and/or transmitting of data from the environmental
sensors 1820 and operational sensors 1920, is not limited to any
particular manner or time, but rather that various suitable schemes are
contemplated. Also, it should be appreciated that in those embodiments in
which a marking device comprises multiple sensors, the sensors need not
operate in the same manner as each other. For example, one or more of the
sensors may operate periodically while one or more may only provide their
data output in response to actuation of the marking device actuation
system. In one embodiment, a plurality of the sensors may provide their
data outputs periodically, but at different rates. Other operating
schemes are also possible.

[0382]FIG. 22 illustrates a functional block diagram of a marking device
2100 including both environmental and operational sensors, according to
another non-limiting embodiment. FIG. 23 illustrates a corresponding
structural representation of the marking device 2100. The marking device
2100 is in significant respects functionally similar to the marking
device 2010 described above in connection with FIGS. 18-20. However,
specific implementation details, such as disposition and distribution of
various components of the marking device, may differ in some respects;
accordingly, unique reference characters are used in the description of
FIGS. 22 and 23, although some of the components described in connection
with these figures may be substantially similar or identical to
components already described above. In some instances, a component
described in previous embodiments as a single element (e.g., the
processor 118) may include multiple components (multiple processors) in
the embodiment of FIGS. 22 and 23, which together perform substantially
the same general functionality as already described above (e.g., but in a
distributed fashion).

[0383]With reference to FIG. 22, the marking device 2100 includes control
electronics, environmental sensors, operational sensors, as well as some
additional components. The control electronics include a processor 2102,
which in this non-limiting example is an Atom® processor available
from Intel Corporation of Santa Clara, Calif. The processor 2102 is on a
processor board 2101 that also includes a temperature sensor 2103
configured to monitor the processor temperature. In this manner, the
processor temperature may be monitored for overheating or other adverse
temperature conditions. The control electronics further comprise a
battery 2104, which provides power to the various components of the
marking device 2100.

[0384]Several of the components of the marking device 2100 are connected
directly to the processor 2102. For example, a compass 2106 is connected
to and provides its output directly to the processor 2102. Similarly, a
location tracking system 2108 (e.g., a GPS receiver, such as the
ISM300F1-C3 GPS module from Inventek Systems of Billerica, Mass.) is
directly coupled to the processor 2102 to provide its output to the
processor. Additionally, the marking device 2100 comprises Wi-Fi
capability, provided by communications interface 124 in the form of a
Wi-Fi module 2110 having a Wi-Fi antenna 2112. The Wi-Fi module is
coupled directly to the processor 2102 via a USB connection, in this
non-limiting example.

[0385]The marking device 2100 further comprises a sensor board 2114, which
is connected to several sensors, itself includes several sensors, and is
coupled to the processor 2102 to provide various data to the processor
2102 and receive control signals from the processor 2102. The sensor
board 2114 comprises two processors, labeled as 2116 and 2118. The
processor 2116, which is a PIC 24 processor in this non-limiting example
(for example, PIC24FJ256GA106-I/PT from Microchip Technology Inc. of
Chandler, Ariz.), may be configured to receive data from various of the
sensors of the marking device 2100, and to communicate with the processor
2102. The processor 2118 may be a dedicated digital signal audio
processor, and may be, for example a PIC 30 processor, such as
DSPIC30F301230ISO-ND from Microchip Technology Inc. of Chandler, Ariz.
Processor 2118 may receive audio input from a microphone, and may process
the audio input and provide it to the processor 2102. The sensor board
2114 further comprises a temperature sensor 2120, configured to monitor
the temperature of the sensor board to determine whether any of the
components of the sensor board are overheating. The sensor board 2114
further comprises an accelerometer 2122, which is a 3-access
accelerometer in this non-limiting embodiment, as well as memory 2123,
which in this non-limiting example is EEPROM.

[0386]As shown, various sensors and other components of the marking device
2100 are electrically coupled to the sensor board 2114, for example to
provide their outputs to the processor 2116. For example, the marking
device 2100 comprises a joystick and user interface buttons 2124, which
provide their outputs to the processor 2116. A technician using the
marking device may use the joystick and buttons 2124 (for example,
joystick SKQUCAA010 from Alps Electric Co., Ltd. and pushbutton module
TL11078F180WQ from E-Switch, Inc. of Minneapolis, Minn.) to interact with
the marking device, for example to navigate menus presented on the
display 2126 of the marking device and to make user-selected entries. The
marking device may further comprise a board 2128 having on it a
temperature sensor 2130, a humidity sensor 2132, and a light sensor 2134.
The temperature sensor 2130 may be configured to detect the air
temperature outside of the marking device. The humidity sensor 2132 may
be configured to detect the humidity of the environment in which the
marking device is located. The light sensor 2134 may be configured to
detect the light intensity, light flux, or illuminance of the environment
in which the marking device is being used. Each of those three sensors
may be connected to the sensor board 2114 and provide their output
signals to the processor 2116.

[0387]Furthermore, the marking device 2100 may comprise various additional
sensors, which, as discussed below with respect to FIG. 23, may be
located in the tip of the marking device. These include a paint can
detection switch 2148, a 3-axis accelerometer 2150, a yaw rate sensor
2152, the previously described microphone 2154, and an RFID module (e.g.,
an RFID read/write module) 2156. The outputs of these sensors may also be
provided to the processor 2116 on the sensor board 2114. In addition, the
marking device may comprise another PIC processor 2158, such as a PIC 18
processor, configured to digitize the output signals of the 3-axis
accelerometer and the yaw rate detector located in the tip of the marking
device prior to providing those outputs to processor 2116.

[0388]The marking device also includes a trigger 2144 for actuating the
marking device. The trigger may be coupled to the sensor board 2114, and
in particular to the processor 2116 in this non-limiting example.
Additionally, a mode selection switch may be associated with the trigger,
such that the processor 2116 may detect not only when the trigger is
actuated, but also what mode is involved. Examples of suitable modes
include paint mode, in which actuation of the trigger causes the
dispensing of a marking material, such as paint, and landmark mode, in
which actuation of the trigger may not result in dispensing of marking
material, but may result in data collection. Other modes are also
possible, as these examples are non-limiting.

[0389]In addition, as shown, the marking device 2100 may further comprise
a speaker 2138, which may be used to provide audio output to the
technician using the marking device. To facilitate this functionality,
the marking device may further comprise an audio board 2140 coupled
between the processor 2102 and the sensor board 2114. The audio board may
receive digital signals from the processor 2102 and convert them to
analog signals, which may be provided to the sensor board 2114 to drive
the speaker 2138.

[0390]Also, as mentioned, the marking device 2100 comprises a display
2126, which may be connected to the sensor board, and which in some
embodiments may be mounted directly to the sensor board 2114.

[0391]Although not shown in FIG. 22, various forms of memory may be
provided with the marking device 2100. For example, the processor 2102
may include RAM as well as a flash memory, or any other suitable types of
memory. Data output from any of the sensors or components of the marking
device 2100 may be stored in the memory of the processor 2102. Each of
the processors 2116 and 2118 may include internal flash memory as well as
RAM.

[0392]To provide electrical isolation between various components of the
marking device, for example to prevent electrical cross-talk or
interference, one or more electrical shields may be included. In the
illustrated embodiment, a shield 2136 may be provided to electrically
shield the compass 2106 from the location tracking system (e.g., GPS
receiver) 2108 and from the processor 2102, as well as to shield the
location tracking system 2108 from the processor 2102. According to one
embodiment, the compass may be shielded by a metallic enclosure (e.g., a
copper box), which may provide shielding from interference caused by
other components of the marking device as well as shielding from the
environment.

[0393]As shown, the marking device also comprises a docking interface 2146
to facilitate docking the marking device to a docking station. The
docking station may be a device configured to receive the marking device
when the marking device is not in use to perform a marking operation, and
may be, for example, any of the types of docking stations described in
U.S. patent application Ser. No. 12/571,411, filed on Sep. 30, 2009 under
Attorney Docket No. D0687.70009US01 and titled "Marking Device Docking
Stations and Methods of Using Same," which is hereby incorporated herein
by reference in its entirety. According to one embodiment, the marking
device may make both electrical and mechanical connection to the docking
station when docked, such that the docking interface may be configured to
provide both electrical and mechanical connection. While docked, the
marking device battery may be charged and/or the marking device may
exchange information with the docking station. For example, the marking
device may transfer any collected marking data to the docking station.
Other functions may also be performed by the docking station, as
described in U.S. patent application Ser. No. 12/571,411.

[0394]Docking events (e.g., docking and de-docking of a marking device)
may be recorded as event entries, for example similar in form to the
event entries of Tables 2-5. Table 14A illustrates an example of event
entry indicating a change in docking status of a marking device. Other
entry formats are also possible.

[0395]In general, the components of marking device 2100 may operate in any
of the manners previously described with respect to marking devices,
environmental sensors, and operational sensors. However, in one
non-limiting embodiment, the various sensors of marking device 2100 may
operate at different rates. As an example, the accelerometers and yaw
rate sensor of the marking device may output their data at relatively
high frequencies, such as in the kHz range, MHz range, or higher. The
temperature sensors, humidity sensor, and light sensor may output their
data at relatively lower frequencies, such as approximately 1 Hz, for
example because those quantities may not change as rapidly as the
quantities measured by the accelerometers and the yaw rate sensor. The
joystick and buttons 2124 may output their data at an intermediate
frequency, for example 10 Hz. Lastly, the RFID sensor of RFID module 2156
may output its data only when the paint can detection switch 2148 changes
state, corresponding to insertion or removal of a paint can. In this
manner, power may be conserved by operating the RFID sensor only when
needed.

[0396]According to one embodiment, the output data from the sensors is
only read and stored upon actuation of the trigger 2144, even though the
sensors may update their outputs at the above-indicated frequencies. Upon
such actuation, data from any one or more of the sensors may be read out
and stored in the memory of processor 2102. The stored data may therefore
represent the values present at the sensors at the time of actuation. In
this manner, data values output by the sensors when the trigger is not
actuated may not be stored in some instances, but rather may be updated
by the subsequent data value from the sensor. In this manner, only the
most recent data from the sensors may be stored upon actuation.

[0397]FIG. 23 illustrates one non-limiting example of a physical
implementation of the marking device 2100 of FIG. 22, utilizing the same
reference numbers as used in FIG. 22. Not all of the components are shown
in FIG. 23.

[0398]As shown, the accelerometer 2150 and a yaw rate sensor 2152 are
located toward the tip 2302 of the marking device 2100 on a first circuit
board. Processor 2158 (for example, a PIC 18 processor, such as a
PIC18F2431-I/SO from Microchip Technology Inc. of Chandler, Ariz.), is
disposed on a second circuit board coupled to the circuit board including
the accelerometer and the yaw rate sensor, and is configured to receive
the outputs from the accelerometer and yaw rate sensor, digitize them,
and send them to the sensor board 2114. The can detection switch 2148 is
included to detect insertion and removal of paint can 2208 from the
marking device. The microphone 2154 is configured to detect sound emitted
when paint is dispensed from the paint can 2208 and provides its output
to processor 2118, shown in FIG. 22. The RFID board 2212 is oriented
vertically within the figure and includes the RFID module 2156, which may
include an RFID reader configured to read an RFID tag on the paint can
2208 or on the lid of the paint can 2208, for example to determine
product information relating to the paint can 2208.

[0399]It should be appreciated that other electrical and physical
configurations of a marking device including one or more environmental
and/or operational sensors are possible, and that FIGS. 22 and 23
illustrate one non-limiting example.

[0400]As mentioned previously, environmental information and/or
operational information output by any one or more environmental sensors
and operational sensors of the marking device (e.g., of the environmental
sensors 1820 and/or operational sensors 1920) may be used for one or more
of various purposes, some of which have been previously described.
Examples of such purposes include assessing whether a marking operation
was or is being performed within environmental and/or operational
tolerances, interacting with the technician and/or controlling/altering
operation of the marking device, and augmenting data records/files.

[0401]To this end, the various environmental information and/or
operational information provided by various sensors may be organized and
handled as data in various formats, and in some implementations may be
organized in terms of events and corresponding event entries formatted
according to a particular protocol, for example as discussed above in
connection with Tables 2 through 5. Event entries similar to these and
including various environmental and/or operational information may be
generated by the marking device at some point once information has been
read/acquired from environmental and/or operational sensors, the event
entries themselves (or any information contained therein) may be logged
in a file for an electronic record, and/or the event entries themselves
(or any information contained therein) may be transmitted by the marking
device (e.g., to remote computer 150).

[0402]In some implementations, environmental information and/or
operational information may be contained within one or more event entries
corresponding to an actuation of the marking device, such that the
environmental information and/or the operational information is part of
an actuation data set. Table 15 below illustrates a modification of an
event entry originally depicted in Table 3 above, in which environmental
information and operational information is included as part of the data
formatted in an actuation state change event entry, according to one
example. The information for acceleration may include three values for
each axis of each accelerometer. One value for a particular axis may be a
raw value, the second value for a particular axis may be a high-pass
filtered value, and the third value may be a low-pass filtered value.
Data values are only shown for one of the two accelerometers listed. As
in Table 3, for purposes of this event format, the actuator is deemed to
have three possible states, i.e., PRESSED, HELD and RELEASED. Marking
information from one or more input devices/other components of the
marking device is recorded with these events to provide information about
the job in progress.

[0403]The contents of an information field for a particular piece of
environmental information and/or operational information in an event
entry may have any of a number of forms; for example, the content may be
strictly numeric (e.g., according to some predetermined scale/units of
measure for the numeric information), alphanumeric (e.g., 78F), text
(e.g., YES), symbolic (e.g., Y or N to indicate "yes" or "no," or some
other symbol to provide an indication, such as ! to indicate sensor
failure or no sensor information available), or referential in nature
(e.g., a filename, pointer or other link to provide an indication of
where relevant information relating to the particular environmental
and/or operational condition may be found).

[0404]In other implementations, one or both of environmental information
and/or operational information may be formatted in one or more particular
event entries generated specifically to provide such information, in a
manner that is not necessarily related to actuation of the marking
device. For example, such "sensor read events" may be generated as the
result of the processor reading one or more environmental and/or
operational sensors one or more times while a job is in progress (e.g.,
on a periodic basis pursuant to processor polls). Table 16 below provides
an example of such a sensor read event entry.

[0405]With respect to file formats for electronic records including event
entries or information derived therefrom, as discussed above any number
of file formats may be employed (e.g., ASCII, XML).

[0406]FIG. 24 illustrates an electronic record 2835, similar to the
electronic record 135 previously described in connection with FIGS. 10
and 13, which may be generated by a marking device 2010 or 2100, stored
in local memory 122 of the marking device, and/or transmitted in whole or
part by the marking device, according to one embodiment. Some or all of
the information provided in the electronic record 2835 may be derived
from an event entry generated by the marking device (e.g., an event entry
is generated and then parsed to provide information in various fields of
an electronic record), or the information contained in the electronic
record 2835 may be provided in another manner pursuant to the concepts
disclosed herein (e.g., sensor information may be acquired directly from
one or more sensors, and acquired information may be stored in the
electronic record without necessarily generating an event entry). In
addition to the information elements shown previously in FIGS. 10 and 13,
the electronic record 2835 may further include one or both of
environmental information 2602 and operational information 2702. While
both types of information are shown for simplicity in FIG. 24, it should
be appreciated that an electronic record according to various embodiments
need not include both environmental information and operational
information.

[0407]The exemplary electronic record 2835 shown in FIG. 24 may be used to
evaluate performance of a marking operation, for example, by reviewing
information in the actuation data set 702C, the ticket information 714,
service-related information 716, the environmental information 2602
and/or the operational information 2702. It should be appreciated that
the electronic record 2835 includes some information that assumes that
the marking device 2010 or 2100 includes the timing system 128 and the
location tracking system 130, such as the timing and location information
shown in the electronic record.

[0408]Table 17 provides an example of a data record that may be generated
by marking device 2010 or marking device 2100 upon actuation of the
actuation system. Each shown "act" corresponds to a separate actuation.
As shown, the data record may include information about the service
provider identification, the user (technician) identification, the
marking device identification, a timestamp (for example, provided by a
timing system such as timing system 128), product data for the marking
material being dispensed, locate request data, and information relating
to the environmental sensors 1820. This example is provided for purposes
of illustration, and is not limiting, as many different forms of data
records may be generated based on the operation of the marking devices
2010 and 2100.

[0409]In a manner similar to Table 17, Table 18 provides another example
of a data record that may be generated by marking device 2010 or 2100
upon actuation of the actuation system. Each shown "act" corresponds to a
separate actuation. As shown, the data record may include information
about the service provider identification, the user (technician)
identification, the device identification, a timestamp (for example,
provided by a timing system such as timing system 128), product data for
the marking material being dispensed, locate request data, and
information relating to the operational sensors 1920. The location
tracking system 130 provides the geo-location data. The temperature
sensor(s) 1922 provides the temperature data. The compass 1924 provides
the heading. The inclinometer 1926 provides the inclination. The
accelerometer(s) 1928 provides the acceleration, which in this embodiment
is a three-axis accelerometer. The yaw rate sensor 1929 provides the yaw
rate. The proximity sensor 1930 provides the distance, which may
represent the distance from the tip of the marking device to the ground,
in one non-limiting embodiment. The pressure sensor 1931 provides the
pressure measurement. This example is provided for purposes of
illustration, and is not limiting, as many different forms of data
records may be generated based on the operation of the marking device
2010 or 2100.

[0410]While Tables 17 and 18 respectively indicate the collection of
environmental information and operational information separately, and as
part of an actuation data set, it should be appreciated that various
embodiments of the present invention are not limited in this respect. In
particular, both environmental information and operational information
may be collected together as part of a given actuation data set.
Furthermore, the inclusion of one or both of environmental information
and operational information in an electronic record such as the record
2835 need not be limited to one or more particular actuations data sets;
rather, in some exemplary implementations, one or both of environmental
information and operational information may be included as a unique
component of an electronic record apart from any particular actuation
data set (e.g., one or both of environmental and operational information
may be common to, or "shared by," one or more actuation data sets).

VIII. ASSESSING OPERATION AND/OR USE OF A MARKING DEVICE

[0411]Environmental information and/or operational information, as well as
any of the other constituent components of marking information and
landmark information discussed herein, may be used to assess whether a
marking device is being used and/or a marking operation was or is being
performed in accordance with recommended practices or within recommended
environmental or operational conditions.

[0412]As an illustrative example, there may be certain preferred
environmental conditions in which a marking device may be used and/or a
marking operation may be performed, particularly with respect to storage,
handling and dispensing of the marking material. In particular, the
marking material manufacturer may specify an ideal temperature, a maximum
temperature, a minimum temperature, an ideal humidity, a maximum
humidity, and the like, for the use of their product. Accordingly, the
use of the marking material above the maximum temperature specification,
below the minimum temperature specification, and/or above the maximum
humidity specification may yield undesirable results, such as an uneven
spray, poor adhesion to the surface on which it is sprayed, and/or poor
durability. This may result in marginally or poorly performed marking
operations, which may have an adverse impact on customer satisfaction and
an increased risk of damage to facilities.

[0413]Additionally, there may be certain preferred process tolerances with
respect to performing marking operations. For example, there may be a
minimum ambient light specification, a certain angle of spray
specification with respect to dispensing of marking material, a certain
distance specification (i.e., distance from target surface) with respect
to dispensing of marking material, a certain motion specification with
respect to sweeping the marking device, and the like. Violations of these
process tolerances may result in poorly performed marking operations,
which may result in poor customer satisfaction and an increased risk of
damage to facilities.

[0414]Other environmental and operational tolerances may also be
applicable to marking operations, and it should be appreciated that those
listed above are non-limiting examples provided for purposes of
illustration.

[0415]In view of the foregoing, according to another aspect of the present
invention, a marking device, or a locate operations system comprising a
marking device, may include an operations monitoring application that
operates in combination with the marking device or that is installed
fully or in part on the marking device. In exemplary implementations
discussed below, an operations monitoring application may provide for
detecting and monitoring the use of locating equipment such as the
marking devices described herein for out-of-tolerance environmental or
operational conditions. For example, with respect to marking material
that is dispensed during marking operations, the operations monitoring
application of the present disclosure may provide for detecting and
monitoring the use of the marking material within the limits of its
product specifications with respect to, for example, the ambient
temperature and humidity. Additionally or alternatively, monitoring may
be based on certain standard operating procedures (e.g., as established
by a facility owner, a locate contractor, a regulatory body, etc.). Other
bases for monitoring the operation of a marking device may also be used.

[0416]According to one aspect of this embodiment, once an out-of-tolerance
condition is detected, either environmental or operational, an
out-of-tolerance alert or notification may be provided to the user
(technician) of the marking device. In some exemplary implementations,
the out-of-tolerance alert may be generated by the control electronics of
the marking device, although not all implementations are limited in this
respect. Additionally or alternatively, a record of such out-of-tolerance
alerts may be stored, such as a record of alert acknowledgments that may
be stored or transmitted by the marking device in response to technician
acknowledgement of the alert.

[0417]An example of an operations monitoring application is now described.
For purposes of illustration, the operations monitoring application is
described in connection with marking device 2010 discussed above in
connection with FIG. 19. However, it should be appreciated that the
operations monitoring application may be used in connection with other
marking devices described herein.

[0418]Referring to FIG. 25, a functional block diagram of an example of an
operations monitoring application 2300 for detecting and monitoring the
use of a marking device (e.g., marking device 2010 in this non-limiting
example) for out-of-tolerance conditions is presented. Operations
monitoring application 2300 may include an operations algorithm 2310,
which is a software algorithm for determining whether out-of-tolerance
environmental and/or operational conditions are present during locate
operations and/or whether violations of certain process operational
tolerances occur.

[0419]To make determinations of out-of-tolerance conditions/occurrences,
operations algorithm 2310 may compare information supplied at an expected
data input 2312 to information supplied at an actual data input 2314. For
example, an operating limits table 2316 may provide the source of
information feeding expected data input 2312. An example of the contents
of operating limits table 2316 is shown in Table 19 below. It should be
appreciated that such a table may include entries for any one or more
conditions sensed by a sensor of the marking device, and that those
entries shown are non-limiting examples.

[0420]The contents of operating limits table 2316 may be informed by
standard operating procedures (SOP) information 2317. In this respect,
the contents of operating limits table 2316 may have a dynamic component.
That is, in the event that the content of SOP information 2317 is
modified and/or that the content of SOP information 2317 varies, for
example from one geographic location to another or from one job/work site
to another, the content of operating limits table 2316 may automatically
vary accordingly. SOP information 2317 may include information, such as,
but not limited to, state, local, and/or regional regulations with
respect to underground facility locate and marking operations; locate
service provider policy information; contractual information; and the
like. Further, SOP information 2317 may include information about the
current industry-accepted best practices and/or procedures with respect
to underground facility locate and marking operations.

[0421]One source of information that may be included in SOP information
2317 may be, for example, the information of the Best Practices Version
6.0 document, published in February 2009 by the Common Ground Alliance
(CGA) of Alexandria, Va. (www.commongroundalliance.com) incorporated
herein by reference in its entirety. The Best Practices Version 6.0
document is a compilation of the current best practices that are
performed with respect to preventing damage to underground facilities.
Another source of information that may be included in SOP information
2317 may be, for example, the information of the Recommended Marking
Guidelines For Underground Utilities as endorsed by the National Utility
Locating Contractors Association (NULCA) of North Kansas City, Mo., which
is incorporated herein by reference in its entirety.

[0422]Generally, the contents of operating limits table 2316 may be
variable and dynamic based on one or more factors, such as, but not
limited to, dynamic information that may be included in SOP information
2317, best practices that may vary with time of year, best practices that
may vary with time of day, best practices that may vary with weather
conditions, best practices that may vary with the skill level of the
locate technician, and the like.

[0423]According to one embodiment, the information supplied to actual data
input 2314 is generated and/or collected in real time during marking
operations that are performed in the field. For example, the source of
information feeding actual data input 2314 may be the marking device
2010, although marking device 2010 is only a non-limiting example, as any
of the marking devices described herein may be used. The actual data
input 2314 may be fed with the data from one or more of the sensors 1820
and 1920, which data is indicated generally in FIG. 25 as sensor data
2322.

[0424]Referring again to Table 19, the values that are contained in
operating limits table 2316 may be expressed in terms that correspond to
the data format that is returned from sensor devices 1820 and 1920. For
example, in one embodiment the light sensor 1826 output may be a voltage,
and thus the ambient light level may be expressed in volts in operating
limits table 2316. However, the values in table 2316 are not limited to
being in any particular format, as discussed above in connection with
Tables 15-18.

[0425]Operations algorithm 2310 may compare the information of operating
limits table 2316 that is present at expected data input 2312 to the
information of sensor data 2322 that is present at actual data input 2314
to determine whether out-of-tolerance environmental and/or operational
conditions and/or violations of certain process tolerances are present
during marking operations. In one example, operations algorithm 2310 may
determine whether marking operations are being performed when the ambient
temperature is too hot or too cold, or when the ambient humidity is too
high. In another example, operations algorithm 2310 may determine whether
the spray angle or spray distance detected during marking operations
exceed acceptable parameters. In yet another example, operations
algorithm 2310 may determine whether marking operations are being
performed when it is too dark, based on a comparison of a sensed light
level to a light level specification.

[0426]When out-of-tolerance environmental and/or operational conditions
and/or violations of certain process specifications are detected,
operations algorithm 2310 may generate out-of-tolerance alerts 2324, the
contents of which may reflect the nature of the out-of-tolerance
condition. The alerts may take any suitable form, such as an audible
alert (a chime, a ring tone, a verbal message or command (e.g.,
synthesized speech provided by a text-to-speech synthesizer of the
marking device), etc., for example presented via speaker 2138), a visual
alert (e.g., a text display presented via display 2126, an indicator
light, etc.), a tactile alert (e.g., vibration of a tactile indicator, as
described below in connection with FIG. 30), any combination of those
options, or any other suitable type of notification.

[0427]Any out-of-tolerance alerts 2324 that are generated may be logged in
an alerts log 2326 of operations monitoring application 2300. Further, in
those embodiments in which the operations monitoring application 2300 is
not loaded and running on the marking device itself, any out-of-tolerance
alerts 2324 that are generated may be transmitted to the marking device
2010, in which the control electronics 112 may process the
out-of-tolerance alerts 2324. For example, control electronics 112 may
receive out-of-tolerance alerts 2324 and present the contents thereof to
the user of marking device 2010 (e.g., visually and/or audibly via the
display 2126 and/or speaker 2138, via a tactile indicator, etc.).

[0428]Additionally, control electronics 112 may generate alert
acknowledgments 2330 that correspond to out-of-tolerance alerts 2324.
Alert acknowledgments 2130 may be returned to operations monitoring
application 2300 and logged in alerts log 2326. Alert acknowledgments
2330 provide evidence that out-of-tolerance alerts 2324 have been
received and processed at marking device 2010. The contents of alerts log
2326 may be useful to various business applications with respect to
marking operations. For example, the contents of alerts log 2326 may be
useful to business applications for assessing the quality of marking
operations that are performed in the field, assessing the skill and/or
competency levels of technicians, and the like. In a specific example,
out-of-tolerance alerts 2324 in alerts log 2326 may be monitored in real
time by, for example, management personnel of locate companies (e.g.,
locate contractors, facility owners) regulatory authorities, or other
agencies, wherein certain actions in response to out-of-tolerance alerts
2324 may be initiated in real time by the management personnel.

[0429]In one implementation, operations monitoring application 2300 may be
installed and executing on a computing device (not shown) that is
separate from marking device 2010, but in communication with the marking
device 2010, such as remote computer 150. In another implementation,
operations monitoring application 2300 may be installed (in memory) and
executing (via one or more processors) on a marking device itself, such
the marking device 2010. In yet another implementation, certain
functionality and/or components of operations monitoring application 2300
may be installed and executing fully or in part on the combination of a
separate computing device and a marking device (e.g., marking device
2010).

[0430]To facilitate operation of a marking device (e.g., marking device
2010) with operations monitoring application 2300 of FIG. 25 when the
application 2300 is executed partly or entirely on a separate computing
device (e.g., remote computer 150), the marking device may have loaded
thereon an operations monitoring client, which may be a counterpart to
operations monitoring application 2300. For example, the operations
monitoring client may be executed by the processor 118 and may process
information of operations monitoring application 2300. Alternatively, the
operations monitoring client may comprise a combination of hardware and
software and/or firmware, which may be coupled to the marking device to
communicate with the processor 118. In such an embodiment, the software
and/or firmware may process information of operations monitoring
application 2300. Alternatively, as noted above, the control electronics
112 of the marking device may include fully or in part operations
monitoring application 2300 itself.

[0431]Table 20 shows an example of sensor data 2322 that may be returned
from environmental sensors 1820 and operational sensors 1920. Further,
sensor data 2322 may include timestamp information, for example from the
timing system 128.

[0432]Non-limiting examples of how the data provided by the environmental
sensors 1820 and operational sensors 1920 may be used by the operations
monitoring application 2300 are now given. It should be appreciated that
numerous other conditions may be detected and acted upon. [0433]1.
Readings from ambient temperature sensor 1822 may be used by operations
monitoring application 2300 to determine whether marking material is
being dispensed while in an out-of-tolerance condition with respect to
ambient temperature. If an out-of-tolerance condition with respect to
ambient temperature is present, an example of the corresponding
out-of-tolerance alert 2324 may be "It is too cold (or too hot) to be
dispensing marking material reliably. Please acknowledge." [0434]2.
Readings from surface temperature sensor 1823 may be used by operations
monitoring application 2300 to determine whether marking material is
being dispensed on a surface whose temperature is in an out-of-tolerance
condition. If an out-of-tolerance condition with respect to surface
temperature is present, an example of the corresponding out-of-tolerance
alert 2324 may be "The surface is too cold (or too hot) to be dispensing
marking material reliably. Please acknowledge." [0435]3. Readings from
humidity sensor 1824 may be used by operations monitoring application
2300 to determine whether marking material is being dispensed while in an
out-of-tolerance condition with respect to humidity. If an
out-of-tolerance condition with respect to humidity is present, an
example of the corresponding out-of-tolerance alert 2324 may be "The
humidity is too high to be dispensing marking material reliably. Please
acknowledge." [0436]4. Readings from light sensor 1826 may be used by
operations monitoring application 2300 to determine whether marking
operations are being performed while in an out-of-tolerance condition
with respect to lighting. If an out-of-tolerance condition with respect
to lighting is present, an example of the corresponding out-of-tolerance
alert 2324 may be "There is insufficient light to be performing marking
operations effectively and/or safely. Please acknowledge." [0437]5.
Readings from location tracking system 130 may be used by operations
monitoring application 2300 to determine whether marking operations are
being performed in an out-of-tolerance condition with respect to
geo-location (e.g., at the wrong location). If an out-of-tolerance
condition with respect to the geo-location is present, an example of the
corresponding out-of-tolerance alert 2324 may be "It appears that you are
at the wrong location. Please suspend operations and check the location
information on the locate request ticket. Please acknowledge." [0438]6.
Readings from one or more operational temperature sensors 1922 may be
used by operations monitoring application 2300 to determine whether a
component of the marking device is overheating. An example of the
corresponding out-of-tolerance alert 2324 may be "Warning. The marking
device is overheating. Please turn off the device and allow it to cool.
Please acknowledge." [0439]7. Readings from compass 1924 may be used by
operations monitoring application 2300 to determine whether the heading
of the marking device is out-of-tolerance. If an out-of-tolerance
condition with respect to heading is present, an example of the
corresponding out-of-tolerance alert 2324 may be "You appear to be
heading in the wrong direction. Please adjust course. Please
acknowledge." [0440]8. Readings from inclinometer 1926 may be used by
operations monitoring application 2300 to determine whether the marking
device is being used in an out-of-tolerance condition with respect to
marking material spray angle. If an out-of-tolerance condition with
respect to marking material spray angle is present, an example of the
corresponding out-of-tolerance alert 2324 may be "Spraying angle is too
shallow (or too steep). Please adjust the spraying angle to be about
perpendicular to target surface. Please acknowledge." [0441]9. Readings
from accelerometer 1928 may be used by operations monitoring application
2300 to determine whether the marking device is being used in an
out-of-tolerance condition with respect to the rate of movement and/or
motion of the marking device during the marking operations. If an
out-of-tolerance condition with respect to the motion is present, an
example of the corresponding out-of-tolerance alert 2324 may be "Spraying
motion is too rapid or too erratic. Please slow down or smooth out the
spraying motion. Please acknowledge." [0442]10. Readings from yaw rate
sensor 1929 may be used by operations monitoring application 2300 to
determine whether the marking device is being used in an out-of-tolerance
condition with respect to yaw rate. If an out-of-tolerance condition with
respect to yaw rate of the marking device is present, an example of the
corresponding out-of-tolerance alert 2324 may be "You are twisting the
device too quickly. Please acknowledge." [0443]11. Readings from
proximity sensor 1930 may be used by operations monitoring application
2300 to determine whether the marking device is being used in an
out-of-tolerance condition with respect to the marking material spray
distance. If an out-of-tolerance condition with respect to marking
material spray distance is present, an example of the corresponding
out-of-tolerance alert 2324 may be "The tip of the marking device is too
close (or too far) from the target surface. Please adjust to between 3
and 6 inches from surface. Please acknowledge." [0444]12. Readings from
pressure sensor 1931 may be used by operations monitoring application
2300 to determine whether the technician is applying sufficient pressure
to an actuation mechanism (e.g., trigger) of the marking device. If an
out-of-tolerance condition with respect to applied pressure is present,
an example of the corresponding out-of-tolerance alert 2324 may be "You
are not applying sufficient pressure to the trigger. Please acknowledge."
[0445]13. In one embodiment the device health sensor 1932 may monitor a
battery level of the marking device. If an out-of-tolerance condition
with respect to the battery level is detected by operations monitoring
application 2300, an example of the corresponding out-of-tolerance alert
2324 may be "The battery of the marking device is too weak to perform
locate operations reliably. Please replace or recharge the battery as
soon as possible. Please acknowledge." [0446]14. Audio provided by audio
recorder 1830 may be used to monitor whether a marking dispenser is
operating appropriately. For example, if an actuation of the marking
device's actuation system is detected but no sound is present from the
audio recorder, an error in the operation of the marking dispenser may be
indicated. An example of a corresponding alert which may be generated is
"The marking dispenser is empty or not functioning. Please investigate.
Please acknowledge."

[0447]Other conditions and events that may arise with the operations
monitoring application 2300 and which may trigger an alert or
notification to the technician include, but are not limited to, the
following: [0448](a) User Input Errors--Action taken by the user, or
suggested by usage pattern is invalid for the current device
configuration; [0449](b) System Malfunction Errors--Marking device
encountered a problem while processing valid data, and was unsuccessful
in automatically correcting this problem; [0450](c) Storage
Errors--Standard data cache of the marking device or extended storage
experiences some error in storing the current data, such as insufficient
storage space or some other storage error; [0451](d) Power
Errors--Marking device has either exhausted the battery supply (e.g.,
power source 114), or an unrecoverable battery/power error was
encountered; [0452](e) Network Errors--The network component (e.g.,
communication interface 124) has experienced an unrecoverable error;
[0453](f) Geographic Location Errors--The GPS component (e.g., location
tracking system 130) has experienced an unrecoverable error; [0454](g)
Marking Material Detection Errors--The RFID component of marking material
detection mechanism 132 has experienced an unrecoverable error; [0455](h)
Actuator Errors--The actuator component (e.g., actuation system 120) has
experienced an unrecoverable error; [0456](i) Synchronization
Errors--Marking device encountered a problem while synchronizing with the
host server (e.g., computer 150) and was unsuccessful in automatically
correcting this problem; [0457](j) Data Accessibility Errors--The
requested data cannot be retrieved due to data corruption, cache locking,
or missing medium; [0458](k) User Input Required--Operator response is
required prior to continuing; [0459](l) Network Connectivity--The network
component (e.g., communication interface 124) has detected a change in
coverage (coverage loss, overage gain, etc); [0460](m) Geographic
Position Accuracy--The GPS component (e.g., location tracking system 130)
has detected a change in overall accuracy (gain or loss of satellite,
WAAS support, etc); and [0461](n) Paint Detection--The RFID component of
marking material detection mechanism 132 has detected a change.

[0462]In the examples above, alert acknowledgments 2330 in response to
out-of-tolerance alerts 2324 may take various forms. In one example, the
technician may acknowledge using the user interface 126, for example by
pushing a button, flipping a switch, or selecting a menu option,
depending on the type of user interface. Different user inputs (buttons,
toggles, menu selections, etc.) may have different meanings with respect
to providing alert acknowledgments 2330. Table 21 below shows an example
of alert acknowledgments 2330, wherein, as a non-limiting example,
certain keys of a user interface of the marking device have certain
meanings.

TABLE-US-00021
TABLE 21
Example alert acknowledgments 2330
Key Meaning
# Indicates an acknowledgement that the alert is received
* Indicates an acknowledgement that the alert is received and that
corrective action is being or has been taken
@ Indicates an acknowledgement that the alert is received and that
marking operations are continuing regardless
$ Indicates an acknowledgement that the alert is received and that
marking operations are (temporarily) suspended

[0463]In another example, a dropdown menu and/or a set of icons that
include the various types of alert acknowledgments 2330, such as shown in
Table 21, may be presented on the display of the marking device. The user
may then select the desired type of alert acknowledgment 2330 from the
dropdown menu and/or icons.

[0464]Also, as mentioned above, out-of-tolerance conditions and other
conditions detected by the environmental and/or operational sensors may
be logged, for example into alerts log 2326, irrespective of whether an
alert is provided to the technician. Thus, for any of the above-described
examples in which an alert may be generated, a log of the detected
condition may also or alternatively be made. Also, other conditions than
those described above may be logged.

[0465]FIG. 26 is a functional block diagram of an example of a locate
operations system 2400 that includes operations monitoring application
2300 of FIG. 25 and the marking device 2010 of FIG. 19. Again, other
marking devices as described herein may be used, and marking device 2010
is described only for purposes of illustration. Locate operations system
2400 may include a central server 2410, which is maintained and operated
by, for example, a locate company, a facilities owner, a regulatory
authority, or other agency (not shown). Central server 2410 may be any
local or centralized computing device that is capable of hosting and
facilitating execution of one or more applications. In implementation,
central server 2410 may be a networked application server and/or web
server that is connected to a network 2412. Examples of personnel that
may be associated with central server 2410 include locate technicians
2414.

[0466]Residing on central server 2410 may be business applications 2416,
which may be any business applications that may be useful with respect to
locate and marking operations. In one example, business applications 2416
may include a locate and marking operations scoring application 2418 that
processes information about locate operations and generates locate
operations scores 2420 that may indicate the degree of quality of
individual locate operations. Additionally, SOP information 2317 may
reside at central server 2410 and may be accessed by operations
monitoring application 2300 and/or any entity of locate operations system
2400 via network 2412.

[0467]For example, locate operations scoring application 2418 may be based
on various embodiments of a quality assessment application, as well as
any one or more of the scoring criteria and/or exemplary metrics
disclosed in connection with such quality assessment applications, as set
forth in U.S. Non-provisional application Ser. No. 12/493,109, filed Jun.
26, 2009, entitled "METHODS AND APPARATUS FOR QUALITY ASSESSMENT OF A
FIELD SERVICE OPERATION," and published as U.S. Patent Publication
2009-0327024-A1, which application is hereby incorporated herein by
reference in its entirety. In particular, a quality assessment
application may be configured to receive a variety of information germane
to locate and marking operations, and compare such information to
expected values or benchmarks (metrics) based on various criteria. A
scoring algorithm implemented as part of some implementations of a
quality assessment application may compare various input information
(e.g., "field information," as obtained from one or more pieces of
locating equipment such as a marking device) to the expected values or
benchmarks to generate a quality assessment score in an automated
fashion.

[0468]In another example, business applications 2416 may include a ticket
approval application 2422 that processes information about locate and
marking operations and generates ticket approval outcomes 2424 that again
may indicate the degree of quality of individual locate and marking
operations. For example, ticket approval application 2422 may be based on
the ticket approval system that is described in U.S. Non-provisional
application Ser. No. 12/204,454, filed Sep. 4, 2008, entitled "TICKET
APPROVAL SYSTEM FOR AND METHOD OF PERFORMING QUALITY CONTROL IN FIELD
SERVICE APPLICATIONS," and published as U.S. Patent Publication
2009-0204466-A1, which application is hereby incorporated herein by
reference in its entirety. This application describes a ticket approval
system for and method of performing quality control (QC) in field service
applications. The ticket approval system may include a work management
server. The work management server may include a ticket approval software
application and a database for storing digital ticket information, such
as field service site identification information, manifest information,
and digital images of field service activities. A method of performing QC
may include, but is not limited to, the field technician completing the
ticket and providing data/images, an approver viewing and selecting a
certain field technician and ticket for quality control review, the
approver reviewing data/images of the selected ticket, the approver
approving the ticket, the approver tagging the ticket for QC, a QC
approver processing QC referrals, the QC approver routing the ticket to a
QC technician, the QC technician completing the QC tasks and updating the
data/images of the selected ticket, the approver tagging the ticket for
coaching, the approver processing coaching referrals, and the approver
performing coaching tasks.

[0469]Network 2412 may be, for example, any local area network (LAN)
and/or wide area network (WAN) for connecting to the Internet. In one
non-limiting embodiment, network 2412 provides the communication link
between any and/or all entities of locate operations system 2400. For
example, network 2412 provides the communication network by which
information may be exchanged between central server 2410, one or more
onsite computers 2430, and/or locating equipment (e.g., marking device
2010) that are used by locate technicians 2414 in the field.

[0470]Onsite computers 2430 may be any computing devices that are capable
of processing and executing program instructions. Onsite computers 2430
may be used by locate technicians 2414 that are performing locate and
marking operations in the field. For example, each onsite computer 2430
may be a portable computer, a personal computer, a tablet device, a
personal digital assistant (PDA), a cellular radiotelephone, a mobile
computing device, a touch-screen device, a touchpad device, or generally
any device including, or connected to, a processor and a user interface.
Preferably, each onsite computer 2430 is a portable computing device,
such as laptop computer or tablet device. Onsite computers 2430 may be
used by locate technicians 2414 to process locate request tickets (not
shown) and to perform locate and marking operations accordingly.

[0471]Additionally, operations monitoring application 2300 may be
installed on onsite computers 2430. For example, operations monitoring
application 2300 may be used to process information received from or
transmitted to marking device 2010. Each onsite computer 2430 may include
a processing unit 2432, which may be any standard controller or
microprocessor device that is capable of executing program instructions,
such as those from operations monitoring application 2300. Each onsite
computer 2430 may also include a quantity of memory 2434, which may be
any data storage mechanism for storing any information that is processed
locally at onsite computer 2430. Processing unit 2432 and memory 2434 may
be used for managing the overall operations of onsite computer 2430.

[0472]Further, each onsite computer 2430 may include a communication
interface 2438 for connecting to network 2412 and/or for communication
with locating equipment. For example, communication interface 2438 may be
any wired and/or wireless communication interface by which information
may be exchanged between any entities of locate operations system 2400.

[0473]Operations monitoring application 2300 is used in locate operations
system 2400 for detecting and monitoring the use of locating equipment
(e.g., marking device 2010) in out-of-tolerance conditions, as described
above. For example, operations algorithm 2310 of operations monitoring
application 2300 determines whether out-of-tolerance environmental and/or
operational conditions are present during locate operations and/or
whether violations of certain process tolerances are present during
locate operations. Optionally, operations monitoring application 2300 may
be used to automatically enable and disable (either electrically,
mechanically, or both) locating equipment in the field based on certain
out-of-tolerance conditions being present.

[0474]Further, locate operations system 2400 is not limited to the types
and numbers of entities that are shown in FIG. 26. Any types and numbers
of entities that may be useful in underground facilities locate
applications may be included in locate operations system 2400. More
details of a method of detecting and monitoring the use of locating
equipment for out-of-tolerance conditions by use of locate operations
system 2400 are described with reference to FIG. 27.

[0475]FIG. 27 illustrates a flow diagram of an example of a method 2500 of
detecting and monitoring the use of locating equipment, such as the
various marking devices described herein, for out-of-tolerance conditions
utilizing, for example, locate operations system 2400 of FIG. 26. As
noted above, the method may be implemented on any suitable combination of
hardware, such as those items shown in FIG. 26, or entirely on the
marking device itself. Method 2500 may include, but is not limited to,
the following steps, which may be implemented in any order.

[0476]At step 2510, onsite computer 2430 or the marking device itself may
detect powering up (e.g., a power on state), and/or one more specific
events (e.g., docking/de-docking of a marking device, one or more
actuations, error conditions, technician interaction with a user
interface, etc.) associated with a marking device, such as marking device
2010 or 2100. Additionally, the relevant SOP information is acquired. For
example, using location tracking system 130 of marking device 2010, the
geo-location of the job/work site may be determined. Based on this
geo-location information, operations monitoring application 2300
automatically queries SOP information 2317 at central server 2410 for the
SOP information of the regulatory body that corresponds to the location
of the work site, which is used to inform operating limits table 2316 of
operations monitoring application 2300.

[0478]At decision step 2512, operations algorithm 2310 of operations
monitoring application 2300 determines whether any out-of-tolerance
conditions are present. For example, if any one of the following
out-of-tolerance conditions is present, method 2500 may proceed to step
2516. However, if none of the following out-of-tolerance conditions are
present, method 2500 may proceed to step 2514. The following
out-of-tolerance conditions are exemplary only and not meant to be
limiting. [0479]1. Readings from ambient temperature sensor 1822 may
indicate an out-of-tolerance condition with respect to ambient
temperature when compared against, for example, the maximum ambient
temperature and/or minimum ambient temperature specifications of
operating limits table 2316 (see, for example, Table 19). [0480]2.
Readings from surface temperature sensor 1823 may indicate an
out-of-tolerance condition with respect to surface temperature when
compared against, for example, the maximum surface temperature and/or
minimum surface temperature specifications of operating limits table 2316
(see, for example, Table 19). [0481]3. Readings from humidity sensor 1824
may indicate an out-of-tolerance condition with respect to humidity when
compared against, for example, the maximum ambient humidity specification
of operating limits table 2316 (see, for example, Table 19). [0482]4.
Readings from light sensor 1826 may indicate an out-of-tolerance
condition with respect to lighting when compared against, for example,
the minimum ambient light level specification of operating limits table
2316 (see, for example, Table 19). [0483]5. Readings from compass 1924
may indicate an out-of-tolerance conditions with respect to heading when
compared against, for example, an expected value. [0484]6. Readings from
inclinometer 1926 may indicate an out-of-tolerance condition with respect
to marking material spray angle when compared against, for example, the
minimum spray angle and/or maximum spray angle specifications of
operating limits table 2316 (see, for example, Table 19). [0485]7.
Readings from accelerometer 1928 may indicate an out-of-tolerance
condition with respect to the rate of movement and/or motion of the
marking device when compared against, for example, the maximum motion
rate specification of operating limits table 2316 (see, for example,
Table 19). [0486]8. Readings from yaw rate sensor 1929 may indicate an
out-of-tolerance condition with respect to yaw rate when compared
against, for example, the maximum yaw rate specification of operating
limits table 2316 (see, for example, Table 19). [0487]9. Readings from
proximity sensor 1930 may indicate an out-of-tolerance condition with
respect to the marking material spray distance when compared against, for
example, the minimum spray distance and/or maximum spray distance
specifications of operating limits table 2316 (see, for example, Table
19). [0488]10. Information from the device health sensor 1932 that is
monitoring the battery of the marking device may indicate an
out-of-tolerance condition with respect to battery strength when compared
against, for example, the minimum battery strength specification of
operating limits table 2316 (see, for example, Table 19).

[0489]At step 2514, operations monitoring application 2300 continues to
monitor the conditions (e.g., environmental and/or operating) of the
marking device during marking operations. For example, operations
monitoring application 2300 at onsite computer 2430 continues to monitor
the conditions of the marking device 2010 during marking operations by
comparing the contents of sensor data 2322 to information in operating
limits table 2316. At the conclusion of this step, method 2500 may, for
example, return to step 2512.

[0490]At step 2516, operations monitoring application 2300 generates the
corresponding out-of-tolerance alert 2324, logs the out-of-tolerance
alert 2324 in alerts log 2326, and transmits the out-of-tolerance alert
2324 to the locating equipment, such as to marking device 2010, in those
embodiments in which the method is not entirely implemented on the
marking device itself. By way of example, the following out-of-tolerance
alerts 2324 correspond respectively to the example out-of-tolerance
conditions of step 2512. The following out-of-tolerance alerts 2324 are
exemplary only and not meant to be limiting. [0491]1. "The ambient
temperature is too cold (or too hot) to be dispensing marking material
reliably. Please acknowledge." [0492]2. "The surface temperature is too
cold (or too hot) to be dispensing marking material reliably. Please
acknowledge." [0493]3. "The humidity it too high to be dispensing marking
material reliably. Please acknowledge." [0494]4. "There is insufficient
light to be performing marking operations effectively and/or safely.
Please acknowledge." [0495]5. "You appear to be heading the wrong
direction. Please adjust course. Please acknowledge." [0496]6. "Spraying
angle is too shallow (or too steep). Please adjust the spraying angle to
be about perpendicular to target surface. Please acknowledge." [0497]7.
"Spraying motion is too rapid or too erratic. Please slow down or smooth
out the spraying motion. Please acknowledge." [0498]8. "You are twisting
the device too quickly. Please acknowledge." [0499]9. "The tip of the
marking device is too close (or too far) from the target surface. Please
adjust to between 3 and 6 inches from surface. Please acknowledge."
[0500]10. "The battery of the marking device is too weak to perform
locate operations reliably. Please replace or recharge the battery as
soon as possible. Please acknowledge."

[0501]At step 2518, one or more out-of-tolerance alerts 2324 are received
at the locating equipment, such as marking device 2010, in those
embodiments in which alerts are not generated on the marking device
itself. The out-of-tolerance alerts 2324 may be presented to the user in,
for example, text form via a display of the marking device, audible form
(e.g., synthesized speech provided by a text-to-speech synthesizer of the
marking device) via a speaker of the marking device, or in any other
suitable manner.

[0502]At step 2520, a certain alert acknowledgment 2330 may be returned to
operations monitoring application 2300. For example, the user, such as a
certain locate technician 2414 may press a certain key of the user
interface of the marking device and initiate the desired alert
acknowledgment 2330, such as those shown above in Table 21. Once the
alert acknowledgment 2330 is received at operations monitoring
application 2300, it may be associated with its originating
out-of-tolerance alert 2324 and logged in alerts log 2326. Subsequently,
operations monitoring application 2300 continues to monitor the operating
conditions of the locating equipment, such as marking device 2010. At the
conclusion of this step, method 2500 may, for example, return to step
2512 and may optionally proceed to step 2522.

[0503]Optionally, method 2500 may include steps to disable locating
equipment until or unless a certain out-of-tolerance condition is
corrected. For example, method 2500 may optionally include the following
steps.

[0504]At optional decision step 2522, certain out-of-tolerance conditions
may carry such importance that the suspension of marking operations is
mandated (e.g., disable actuations so as to impede dispensing of
markers). One such out-of-tolerance condition may be the out-of-tolerance
condition with respect to temperature. Another such out-of-tolerance
condition may be the out-of-tolerance condition with respect to humidity.
Yet another such out-of-tolerance condition may be the out-of-tolerance
condition with respect to lighting. Still another such out-of-tolerance
condition may be the out-of-tolerance condition with respect to
geo-location. Other out-of-tolerance conditions may also be sufficiently
important to mandate suspending marking operations, and those examples
listed are non-limiting. In these examples, operations monitoring
application 2300 may wait a certain amount of time (e.g., 1 minute) from
the initial detection of the out-of-tolerance conditions and again
acquire sensor data 2322 to determine whether the out-of-tolerance
condition is still present or has been corrected. If the out-of-tolerance
condition has been corrected, method 2500 may proceed to step 2524.
However, if the out-of-tolerance condition has not been corrected, method
2500 may proceed to step 2526.

[0505]At optional step 2524, the locate technician 2414 continues to
perform marking operations and operations monitoring application 2300
continues to monitor the conditions of the marking device. At the
conclusion of this step, method 2500 may, for example, return to step
2512.

[0506]At optional step 2526, the marking device may be disabled. For
example, actuation system 120 of marking device 2010 may be disabled so
as to impede dispensing of marking material. The action to disable may be
logged in alerts log 2326.

[0507]At any time during the steps of method 2500, the contents of alerts
log 2326 may be processed by business applications 2416. In one example,
alerts log 2326 may be processed by locate operations scoring application
2418 and/or ticket approval application 2422 for assessing the quality of
locate and marking operations that are performed in the field, assessing
the skill and/or competency levels of locate technicians, and the like.

[0508]While FIGS. 25-27 illustrate some non-limiting examples of manners
in which data provided by environmental sensors and/or operational
sensors of a marking device may be used, other uses are also possible.
For example, the data from environmental sensors 1820 and/or operational
sensors 1920 may be used to trigger alerts or notifications to a
technician irrespective of whether the sensed condition is outside
tolerances. For example, in some instances there may not be a specific
tolerance for a given environmental or operational condition, and yet an
alert to the technician may be generated for the purpose of making the
technician aware of whatever value the sensed condition has taken. Thus,
the generation of alerts/notifications/warnings based on sensed
environmental and operational conditions is not limited to those
instances in which the sensed condition takes any particular value(s).
Also, as previously explained, the notification signal may take any
suitable form, such as an audible alert (a chime, a ring tone, a verbal
message or command (e.g., synthesized speech provided by a text-to-speech
synthesizer of the marking device), etc.), a visual alert (e.g., a text
display (for example, in those embodiments in which the marking device
includes a display), an indicator light, etc.), a tactile indication, any
combination of those options, or any other suitable type of notification.

[0509]Also, it should be appreciated that information from one or more of
the environmental sensors 1820 and/or operational sensors 1920 may be
used more generally to control or alter operation of the marking device.
For example, one or more components of the marking device 2010 or 2100
may be activated, enabled, or disabled, or the functionality thereof
controlled or altered in some manner, in response to one or more of the
environmental sensors 1820 and/or operational sensors 1920 providing
environmental information and/or operational information indicative that
such control should be exhibited. Such activation, enablement, and/or
disablement may be electrical in nature (e.g., providing power or an
enable signal, triggering operation of a sensor, etc.), mechanical in
nature (e.g., causing a locking mechanism to be engaged on the actuation
system) or both. For example, if the surface temperature sensed by
surface temperature sensor 1823 is outside of acceptable tolerances for
dispensing of a marking material (such as paint), the actuation system
120 may be disabled, thus preventing dispensing of a marking material. If
the sensed inclination of the marking device as sensed by inclinometer
1926 is unsuitable for dispensing of a marking material (such as paint),
the actuation system 120 may be disabled, thus preventing dispensing of
the marking material. Similarly, if the acceleration as sensed by
accelerometer 1928 is out-of-tolerance with accepted practices, the
actuation system 120 may be disabled. If a sensed condition is
out-of-tolerance, the operation of one of the environmental and/or
operational sensors may be altered, for example by altering the sampling
rate to collect more or less data. According to one embodiment, the
sampling rate of a location tracking system of the marking device may be
increased in response to an out-of-tolerance heading detected by the
compass of the marking device. According to another embodiment, the
sampling rate of the location tracking system may be increased in
response to the location tracking system detecting an out-of-tolerance
location. Other control actions are also possible, and the aspects
described herein relating to controlling the marking device in response
to sensing environmental and/or operational conditions are not limited in
the types of actions that may be taken or the sensed conditions which may
trigger action/alteration.

[0510]Furthermore, the determination of whether a condition or multiple
conditions are out-of-tolerance, whether to generate an alert or
notification to a technician, or whether to control/alter some
functionality of the marking device based at least in part on
environmental and/or operational information, may be made in any suitable
manner. For instance, as illustrated in some of the foregoing examples,
such a determination may be made by comparison of a single value from a
sensor to an expected or target value. Alternatively, outputs from the
environmental sensors and/or operational sensors may be monitored for
changes (e.g., any change, or by some predetermined amount), rather than
for a particular single value. For example, a change in temperature, or a
change in light, may initiate generation of an alert, rather than a
single temperature or light value.

[0511]In addition, information provided by one or more of the
environmental sensors and/or operational sensors may be monitored and
analyzed to detect patterns. For example, information provided by the
operational sensors may be used to formulate and assess patterns of
operation of a particular technician, which may be thought of as
technician "signatures." As an example, a particular technician may have
a characteristic motion when performing a marking operation, such as
painting an arrow on the ground, or may perform the operation at a
characteristic speed. Assessing information provided by the one or more
accelerometers 1928, for example, may allow for determination of the
unique characteristic. Once determined, information from the operational
sensors on future jobs may allow for identification of the technician
based on the unique characteristic, and may also be used to assess
whether the technician is operating in his/her normal manner or whether
he/she is deviating from his/her usual operation, which may suggest that
the technician was doing something out of the ordinary, and which
accordingly may cause generation of an alert/notification and/or
alteration of the marking device. Such information, therefore, may be
used for quality control and/or for training purposes of technicians.
Similarly, such operating information from multiple technicians may be
used to develop standard operating guidelines or protocols.

[0512]It should be appreciated from the foregoing discussion that
information provided by two or more of the environmental sensors may be
used in combination, for example to assess the environmental conditions,
to interact with the technician (e.g., generate an alert), and/or to
control/alter operation of the marking device (e.g., disable or enable
actuation of the marking device). As a non-limiting example, the sensed
ambient temperature in combination with the sensed humidity may provide
information about whether a particular form of precipitation is present
(e.g., snow, rain, etc.), in response to which an alert may be generated
and/or one or more components of the marking device may be enabled or
disabled (e.g., the actuation system may be disabled). Non-limiting
examples of useful combinations of environmentally sensed conditions
include: ambient temperature+humidity; surface temperature+humidity;
ambient temperature+surface temperature; ambient temperature+light
sensor; light+image capture; light+audio capture; and ambient
temperature+humidity+light. However, it should be appreciated that other
combinations are also possible.

[0513]It should also be appreciated from the foregoing discussion that
information provided by two or more of the operational sensors may be
used in combination, for example to assess the operational conditions of
a marking device, to interact with the technician, to assess, determine
and/or analyze technician "signatures" associated with device
use/manipulation, and/or to control or alter operation of the marking
device (e.g., to disable actuation of the marking device, enable
actuation of the marking device, etc.). Non-limiting examples of useful
combinations of sensed operational conditions which may be used for any
of the purposes described above include: acceleration of marking
device+proximity of marking device to surface; proximity of marking
device to surface+inclination of marking device; acceleration+heading;
geo-location+heading+acceleration; and
geo-location+acceleration+inclination. However, it should be appreciated
that other combinations are also possible.

[0514]Furthermore, according to one embodiment, information provided by
one or more environmental sensors may be used in combination with
information provided by one or more operational sensors, for example to
assess the quality of the marking operation, to interact with the
technician, to assess, determine and/or analyze technician "signatures"
associated with device use/manipulation, and/or to control or alter
operation of the marking device (e.g., disable or enable actuation of the
marking device). For example, when dispensing marking material, the angle
at which the marking dispenser may be suitably held may depend on the
surface temperature on which the marking material is being dispensed.
Thus, information from an inclinometer and a surface temperature sensor
of the marking device may be considered in combination to assess whether
a technician is performing a marking operation appropriately, and may
trigger any of the actions described above. Other combinations of sensor
information may also be useful depending on a particular application.

IX. GROUP MODE AND SOLO MODE

[0515]As previously explained, the marking devices described herein may be
used in different modes, examples of which include marking mode and
landmark mode. In addition, marking devices according to one aspect of
the present invention may be operated in a so-called "solo mode" or a
so-called "group mode."

[0516]For some marking operations, a single technician may be present at
the jobsite and may complete the marking operation. Thus, any marking
data collected relating to the job may be solely from the technician's
marking device and may not need to be combined with marking data from any
other marking devices. In such situations, the marking device may be
operated as an individual, independent marking device in solo mode. As
described above, data collected by the marking device may be stored
locally and/or transmitted to a host server, such as remote computer 150.

[0517]For certain types of underground facility locate operations,
multiple locate technicians may be working on a same locate ticket
simultaneously. When this occurs, it may be advantageous for some or all
of the marking devices that are used during performance of the ticketed
job to consolidate data, such as by providing data to one of the marking
devices or to a host server. This may be accomplished through the use of
a group mode of operation of the marking devices. In group mode, a
marking device may act as a "worker" device, and may not be capable of
transmitting its collected marking data to a remote computer. For
example, the wireless transmission capability of the marking device may
be disabled in group mode. Rather, the marking data may be cached in
local memory 122 of the marking device, or may be transmitted to another
marking device, which may act as a "leader" device, receiving the
collected marking data from the other marking devices used for the
marking operation. The leader marking device may then transmit the
collected marking information to a remote computer, or may handle the
collected information in any suitable manner.

[0518]Selection of solo mode and group mode may be accomplished in any
suitable manner. For example, selection between these two modes may be
facilitated by any suitable combination of hardware and/or software on
the marking device. For example, the marking device may include mode
controller software for selecting the operating mode of the marking
device. According to one embodiment, the user interface of the marking
device may include a toggle switch for toggling between solo mode and
group mode. Alternatively, the marking device may present the technician
with a menu on a graphical display of user interface 122, from which the
technician may choose the desired mode. Other schemes for allowing
selection of solo mode and group mode are also possible.

X. ENHANCEMENTS TO DETERMINATION OF DISPENSING LOCATION OF MARKING
MATERIAL

[0519]As mentioned previously, in some situations it may be desirable to
know the location of any marking material dispensed by a marking device.
According to some embodiments, the location of any dispensed marking
material may be approximated by the location of virtually any point on
the marking device itself (e.g., by acquiring geo-location information
from a location tracking system coupled to the marking device).

[0520]In one exemplary embodiment, the accuracy of the dispensing location
of marking material may be improved by selecting a point on the marking
device sufficiently close to the point from which marking material is
dispensed. For example, in some implementations, the marking material may
be dispensed near the tip of the marking device, such that determination
of the location of the tip of the marking device may provide a
sufficiently accurate approximation of the location of the dispensed
marking material, and therefore a determination of the resulting marking
pattern (e.g., dots, lines, arrows, lettering, etc.). In addition,
determining the motion of the tip of the marking device may allow for
assessment of technician manipulation of the marking device, which may be
used for quality control, training purposes, and standard setting, among
other things.

[0521]Thus, according to another aspect of the present invention, methods
and apparatus are provided for determining the location of the tip of a
marking device. However, it should be appreciated that the tip of the
marking device is a non-limiting example of a specific point of a marking
device for which it may be desirable to know the location, as, for
example, other portions of the marking device may be closer to the point
from which marking material may be dispensed depending on the
configuration of the marking device. The methods and apparatus described
herein may be applied equally well to the determination of any point of
interest on the marking device.

[0522]One approach for determining the location of the tip of the marking
device (e.g., tip 2302 shown in FIG. 23), or any other point of interest
on the marking device, is to place a location tracking system at that
point. Thus, according to one embodiment, a marking device, such as any
of the marking devices described previously herein, or any other marking
device, may include a location tracking system 130 as discussed in other
embodiments (e.g., a GPS receiver), wherein the location tracking system
is disposed at or sufficiently near the tip of the marking device,
allowing for determination of the location of the tip of the marking
device. Thus, the location tracking system 130 may provide the
geo-location of the tip of the marking device, which, as mentioned, may
be useful for at least two reasons. First, because of the close proximity
of the location tracking system 130 to the point from which marking
material is dispensed, the geo-location information provided may be used
as an indicator of the location of any dispensed marking material.
Secondly, the geo-location information provided by the location tracking
system may be used to record the motion of the tip of the marking device,
which, as mentioned, may be used for various purposes, including
detection of out-of-tolerance operation of the marking device,
determination of operating patterns of technicians, etc.

[0523]While the above-described embodiment provides a location tracking
system positioned at the point of interest on the marking device, such
positioning of a location tracking system may not always be possible or
advantageous. For example, as explained previously herein, in some
embodiments the operation of the location tracking system may be
facilitated by positioning the location tracking system toward the top of
the marking device, for example if the location tracking system is a GPS
receiver. However, as mentioned, it may be desirable in some embodiments
to determine the location of the tip of the marking device, or any other
point of interest of the marking device, which in some situations will
not correspond to the top of the marking device. Thus, according to one
embodiment, methods and apparatus are provided for determining the
location of a point of interest of a marking device when a location
tracking system is located at a different point on the marking device.
For simplicity of explanation, the following examples will be discussed
assuming that a location tracking system is located near the top of the
marking device and that the point of interest of the marking device is
the tip of the marking device. It should be appreciated that the
described apparatus and techniques may apply equally well to other
positions of the location tracking system and points of interest on the
marking device.

[0524]To facilitate the following discussion, it is useful to first
consider the physical configuration at issue for determining the location
of the tip of the marking device when the location tracking system is
located at or near the top of the marking device. For this purpose, the
marking device may be represented in simplified form as an elongated rod
or stick. FIG. 28 illustrates a perspective view of such a simplified
representation of a marking device, shown as marking device 3000.

[0525]In FIG. 28, the x-y plane represents the ground and the z-direction
represents the vertical direction perpendicular to the ground. The point
P1 may be the location of a location tracking system (e.g., a GPS
receiver), and in some embodiments may correspond generally to the top of
the marking device, for example near where the technician may hold the
marking device if it is a handheld device. The point P2 represents the
point of interest of the marking device, and in this non-limiting example
corresponds generally to the tip of the marking device. The point P2 may
be assumed to be at ground level, i.e., in the x-y plane (z=0) for
purposes of simplicity, except as described below in those embodiments in
which the distance of P2 from the x-y plane may be measured. The shortest
distance between P1 and P2 is given by L, which in some embodiments may
correspond to the length of the marking device, although not all
embodiments are limited in this respect. For example, if the marking
device has a non-linear shape, the distance L may not correspond to the
length of the marking device. The marking device 3000 may be projected
onto the x-y plane (z=0) along the dashed line 3002, which therefore lies
in the x-y plane. The distance between the points P1 and P2 in the x-y
plane (i.e., along the dashed line 3002) is represented by d. The
distance between the point P1 and ground is given by H (i.e., z=H). At
any given time, the marking device may make an angle θ with respect
to the x-y plane, i.e., with respect to ground in this non-limiting
example. The projection of the marking device on the x-y plane, i.e.,
along the line 3002, may be at an angle φ in the x-y plane with
respect to the x axis. In some embodiments, the x-axis may be defined to
align with true North, although not all embodiments are limited in this
respect.

[0526]According to one embodiment, a marking device, such as marking
device 3000, may comprise a location tracking system at the point P1. The
location tracking system may provide the geo-location of the point P1
with respect to the x-y plane, represented as GPSo. The geo-location
of P2 in the x-y plane may be represented by GPS'. As will be explained,
GPS' may be determined based on a value of GPSo given by a location
tracking system and determination of suitable combinations of L, d, H,
θ, and φ. The value of L may be known before the marking
operation begins, for example since it may be set after manufacture of
the marking device. The values of d, H, θ, and φ may be
directly sensed during operation of the marking device or may be
calculated using suitable ones of the operational sensors 1920, as will
be described below.

[0527]According to one embodiment, the geo-location of the tip of a
marking device, such as marking device 3000, may be determined using the
value of GPSo given by the location tracking system at P1 and
accelerometer data from an accelerometer positioned at or sufficiently
near the tip of the marking device (i.e., at point P2 in FIG. 28). In
this embodiment, it is assumed that the value of L is known or determined
in any suitable manner. The accelerometer in this non-limiting embodiment
is a 3-axis accelerometer. By suitable analysis of the acceleration
values for each axis, using known algorithms, the angle θ that the
marking device 3000 makes with the ground may be determined (see, e.g.,
the previous discussion of how to use an accelerometer as an
inclinometer, as described by Shanghai Vigor Technology Development Co.).
Based on the known distance L and the determined angle θ, the
distance d between GPSo and GPS' in the x-y plane may be calculated
(using the fact that the cosine of φ is equal to d/L).

[0528]Once the distance d is known, the value of GPS' may be derived from
GPSo if the angle φ is known, since φ may provide the
direction from GPSo to GPS' (again, in some embodiments the x-axis
may be aligned with, or taken as, true North, such that φ may
represent an angle with respect to true North). The value of φ may be
determined in one of several manners. One manner for determining φ is
from the readout of a compass of the marking device, such as previously
described compass 1924. If the location tracking system providing
GPSo is a GPS receiver, then the value of φ may alternatively be
taken from the heading information provided as part of the NMEA data
stream provided by the GPS receiver. A third alternative for determining
φ is to calculate a direction of motion based on multiple GPS points
taken from the location tracking system. According to this third
alternative, multiple GPS points taken at different times may be used to
calculate a direction of motion by, for example, determining the
direction indicated by a straight line connecting the multiple GPS
points. Other methods for determining φ are also possible, as these
are non-limiting examples. Once φ is known, the value of GPS' may
then be determined from GPSo, d and φ. Once GPS' is determined,
it may be used instead of GPSo (or in addition to GPSo) as more
accurate geo-location data, which may be included, for example, in one or
more event entries and/or electronic records as discussed above.

[0529]According to an alternative embodiment, the value of GPS' may be
determined from a measured value of GPSo using an inclinometer on
the marking device, such as inclinometer 1926, previously described. The
inclinometer may provide the value of θ. In this embodiment, it is
assumed that the value of L is known or determined in any suitable
manner. Thus, the value of d may be determined using L and θ, as
explained above. The value of φ may be determined in any suitable
manner, for example using any of the techniques described above. The
value of GPS' may then be determined from GPSo, d, and φ, as
noted above.

[0530]According to another embodiment, the value of GPS' may be determined
from a measured value of GPSo using a proximity sensor, such as
previously described proximity sensor 1930. In this embodiment, it is
assumed that the value of L is known or determined in any suitable
manner. The proximity sensor may be positioned at P1 and configured to
measure the value of H. Assuming that the point P2 is at or very near the
ground (i.e., having a vertical height of approximately zero), the value
of H and the known distance L of the marking device may be used to
determine d, for example using the Pythagorean theorem. The value of
φ may be determined in any suitable manner, for example using any of
the techniques described above. The value of GPS' may then be determined
using GPSo, d, and φ.

[0531]As explained, the above-described example, in which a single
proximity sensor is used to determine the value of H, may provide
suitable results when it is assumed that the point P2 has zero vertical
height. In one embodiment, that assumption may be avoided by also
including a proximity sensor at the point P2 and configured to measure
the distance between P2 and the ground. Then, the difference in height
between P1 and P2 (rather than the value of H) may be used in connection
with the known distance L to determine the distance d (e.g., using the
Pythagorean Theorem). The value of φ may be determined in any
suitable manner, for example using any of the techniques described above.
The value of GPS' may then be determined using GPSo, d, and φ.

[0532]According to a further alternative embodiment, the value of GPS' may
be determined from a measured value of GPSo using two 3-axis
accelerometers on the marking device. One accelerometer may be located at
the point P1 on the marking device, while the second may be located at
the point P2. Using the techniques described in U.S. Patent Application
Publication 2008/0255795, which is incorporated herein by reference in
its entirety, the location of P2 relative to P1 may be determined.

[0533]As mentioned, in some instances it may be desirable to track the
motion of a specific portion of a marking device, such as the tip of the
marking device, for any one of the reasons previously described. In those
embodiments in which the marking device includes a location tracking
system providing a value of GPSo for a different point on the
marking device than the point of interest, the tracking of the point of
interest may be performed by determining GPS' (the location of the point
of interest) for each value of GPSo as the marking device is moved
using any of the above-described techniques.

[0534]However, in some instances, the value of GPSo provided by the
location tracking system may not have sufficient accuracy to allow for a
desired level of accuracy in tracking the motion at the desired point on
the marking device (e.g., the point P2). For example, when performing a
marking operation, a technician may make marking patterns that are
relatively small compared to the resolution of the location tracking
system. For example, the technician may make lines, arrows, write words,
or make other patterns that have details smaller than the resolution of
the location tracking system (e.g., smaller than approximately 30 inches
in some embodiments). In such instances, using the above-described
techniques for determining GPS' as the point P2 moves may not
sufficiently capture the movement with a desired resolution. Thus, the
techniques described below may be used.

[0535]According to one embodiment, the motion of the point P2 may be
tracked by using any of the above-described techniques to get an initial
value of GPS' and then using data from an accelerometer at the point P2
to determine the distance traveled in the x and y directions. This
technique is commonly referred to in the relevant arts as "dead
reckoning." In this embodiment, the accelerometer may provide
acceleration data for the x and y axes. That data may be integrated twice
to determine the total distance traveled in the x and y directions, thus
giving the position of P2 at any point in time relative to any initial
GPS' value. Alternatively, the accelerometer may output velocity data for
each axis, which may be integrated to determine the total distance
traveled in the x and y directions. A specific example is now described
with respect to FIG. 29.

[0536]FIG. 29 illustrates a top view of a non-limiting example of a
marking pattern 2800 that may be made by a technician using one of the
marking devices described herein. The marking pattern 2800 comprises
lines 2802a-2802f, which may be painted lines in those embodiments in
which the marking material is paint. Those lines are represented in FIG.
29 as solid lines because they correspond to when the actuation system of
the marking device (e.g., actuation system 120) is activated to dispense
marking material. Lines 2804a and 2804b, described below, are shown as
dashed lines because the actuation system is not actuated as the marking
device traversed the paths indicated by those lines and therefore no
paint was dispensed.

[0537]The making of the marking pattern 2800 by a marking device may be
determined as follows. First, the technician may begin the marking
pattern at the point R1, at which time the technician actuates the
actuation system to begin dispensing marking material. The location of
point R1 may correspond to the initial location of the tip of the marking
device and therefore may be determined from a value of GPSo of the
top of the marking device and any of the above-described techniques for
determining the location of the tip relative to the location of the top
of the marking device.

[0538]The technician may then begin to move the marking device along the
path indicated by line 2802a, ending at the point R2. The motion of the
tip of the marking device along line 2802a may be determined from the
output of an accelerometer at the tip of the marking device, providing an
output signal for both the x and y directions. According to one
embodiment, the output of the accelerometer is velocity data for both the
x and y axes, and is output periodically, for example twice per second,
although higher and lower data output rates are possible. The velocity
values for each of the x and y axes may be multiplied by the time
duration between samples of the accelerometer (e.g., one-half of a second
in this non-limiting example) to get the distance traveled in the x and y
directions from the initial point R1. Alternatively, the total velocity
of the marking device may be multiplied by the time duration between
samples of the accelerometer, and the direction of motion may be
determined by comparing the velocity values for the x and y axes to each
other, e.g., by taking the ratio of the velocity along the x-axis to the
velocity along the y-axis. Either way, the distance traveled in the x and
y directions may be determined.

[0539]In the non-limiting example of FIG. 29, the first line painted by
the technician, i.e., line 2802a, may serve as a base line or reference
line, from which the angle of subsequent motions may be referenced. Thus,
in FIG. 29, the angle of the second motion of the technician, from points
R2 to R3 along the path indicated by line 2804a may be determined by
reference to the direction of line 2802a since the accelerometer output
will indicate a change from the motion along the path of line 2802a. The
distance and direction of the line 2804a may be determined as described
above for line 2802a. Again, the line 2804a is shown as a dashed line, as
the actuation system of the marking device is not activated while the
marking device traverses the illustrated path.

[0540]The marking device is subsequently moved along line 2802b (from
point R3 to R4), then along line 2804b (from point R4 to R5), then along
line 2802c (from point R5 to R6), along line 2802d (from point R6 to R7),
along line 2802e (from point R7 to R8), and finally along line 2802f
(from point R8 back to point R5). The length and relative direction of
each of the indicated lines may be determined as described above for line
2802a.

[0541]Thus, it should be appreciated that according to this non-limiting
embodiment, a value of GPSo provided by a location tracking system
is used only to determine the initial location of R1, after which the
locations of points R2-R8 are determined using dead reckoning.

[0542]Also, it should be appreciated that while the relative orientation
of each of the indicated lines is determined from the dead reckoning
techniques described, the absolute, or actual, orientation is not
determined from the accelerometer data since the actual orientation of
line 2802a is not determined from the accelerometer data. Thus, according
to one embodiment an additional step of determining an actual orientation
of the line 2802a may be performed. According to one non-limiting
embodiment, the actual orientation of line 2802a may be given by a
heading provided by a compass of the marking device while the line 2802a
is made. Other techniques may alternatively be used to determine the
actual direction of the first motion of the marking pattern.

[0543]According to the above-described embodiment, the location of the tip
of a marking device may be determined by determining an initial location
using a location tracking system and subsequently using the dead
reckoning techniques described. Because the error associated with dead
reckoning may increase as the distance traversed increases, it may be
desirable in some embodiments to "reset" the dead reckoning by
determining a new initial location value using a location tracking
system. For example, referring to the marking pattern 2800, in one
embodiment the location of R1 may be determined from a value of GPSo
given by a location tracking system and any of the techniques described
for determining a value of GPS' for the given GPSo. Subsequently,
dead reckoning may be used to determine the paths of lines 2802a, 2804a,
2802b, and 2804b. According to one embodiment, the location of point R5
is not determined from dead reckoning, but rather may be determined by
getting a value of GPSo at the point R5 and calculating a
corresponding value of GPS'. Then, dead reckoning may be used to
determine the locations of lines 2802c-2802f. In this manner, location
errors that accumulate using dead reckoning may be minimized or
eliminated.

[0544]Accordingly, it should be understood that a new initial location
point serving as a starting point for the use of dead reckoning may be
set at any suitable intervals during a marking operation. Suitable
criteria for determining when to set a new initial location point for the
use of dead reckoning include setting a new initial point for the
beginning of each new mark that a technician makes (e.g., each new line,
arrow, letter, etc.), for each new marking pattern (e.g., a dotting
pattern, a lines pattern, etc.), for each new marking job, or every time
the dead reckoning data indicates a threshold total distance has been
traveled (e.g., 5 meters, 10 meters, 50 meters, or any other threshold
value). This list is not exhaustive, as other criteria may also be used
to determine when to set a new initial location point for the use of dead
reckoning.

XI. ENHANCED USER INTERFACE

[0545]According to one aspect of the present invention, a marking device
may include an enhanced user interface with tactile functionality. As
will be described, the tactile functionality may be provided in one or
more of various locations on the marking device, and may be used for
various purposes.

[0546]FIG. 30 illustrates an example of a portion of a marking device 2900
including multiple tactile indicators for providing a tactile indication
to a technician using the marking device. The marking device 2900 may be
a marking device according to any of the embodiments previously described
herein. The marking device 2900 includes a body 2910, control electronics
2912, a handle 2914 and an actuator 2916. In addition, the marking device
2900 includes a user interface including a display 2918, a joystick 2920,
and arrow selection buttons 2922. As compared to the user interfaces of
the marking devices previously described, the user interface of the
marking device 2900 also includes three tactile indicators, 2924a-2924c,
which may alternatively be referred to as vibrating devices or vibrators.

[0547]The tactile indicator 2924a is disposed within or on the handle 2914
of the marking device 2900, or otherwise mechanically coupled to the
handle 2914. The tactile indicator 2924b is disposed within or on the
joystick 2920, or is otherwise mechanically coupled to the joystick 2920.
The tactile indicator 2924c is disposed within or on the actuator 2916,
or otherwise mechanically coupled to the actuator 2916. It should be
appreciated that marking devices including tactile indicators according
to the embodiments described herein are not limited to having any
particular number of tactile indicators (i.e., one or more) and are not
limited in the locations at which the tactile indicators are placed.

[0548]The tactile indicators may be of any suitable type. One example of a
suitable type of tactile indicator is that used in cellular telephones to
provide the "vibrate" functionality. According to one embodiment, one or
more of the tactile indicators is formed by a flywheel that has a weight
configured to unbalance the flywheel, so that when the flywheel spins it
wobbles. According to one embodiment, all three of the tactile indicators
are the same type, although not all embodiments are limited in this
respect.

[0549]The tactile indicators 2924a-2924c may provide any suitable type of
tactile indication to a technician, in terms of duration, frequency,
intensity, pattern, and any combinations thereof. Also, the tactile
indicators 2924a-2924c need not provide the same type of tactile
indication. For example, tactile indicator 2924a may provide a relatively
strong, continuous vibration of long duration, whereas tactile indicator
2924b may provide a series of low intensity, short vibrations.
Furthermore, one or more of the tactile indicators may be configurable to
provide multiple different types of tactile indications. For example, in
some instances the tactile indicator 2924a may provide a long, continuous
vibration, whereas in other instances the tactile indicator 2924a may
provide a short vibration. Thus, the type(s) of tactile indication
presented by the tactile indicators is not limiting.

[0550]According to one embodiment, the tactile indications provided to a
user may have different meanings. According to one embodiment, the
meaning may differ depending on the tactile indicator providing the
tactile indication. For example, vibration of the tactile indicator 2924a
may indicate the marking device power supply is low, while vibration of
the tactile indicator 2924b may indicate the technician has tried to
select an invalid entry for a menu displayed on display 2918, and
vibration of the tactile indicator 2924c may indicate that the actuator
2916 is not functioning. According to one embodiment, different meanings
may be conveyed by a single tactile indicator. For example, a short
vibration of tactile indicator 2924a may indicate the marking device
power supply is low, while a longer duration vibration of tactile
indicator 2924a may indicate, for example, that the marking device is not
at the correct job location, for example as may be determined by a
location tracking system of the marking device. Thus, it should be
appreciated that the tactile indicators may be used to convey various
messages to the technician.

[0551]According to one aspect of the present invention, one or more of the
tactile indicators 2924a-2924c may operate in response to information
collected by an environmental sensor and/or operational sensor of the
marking device. For example, as described above (e.g., in connection with
FIG. 25), some embodiments of the present invention provide an alert or
notification to the marking device technician if an out-of-tolerance
condition is detected based on a condition sensed by an environmental or
operational sensor. As explained, the alerts may take any suitable form
including visual and/or audible. In addition, or alternatively, the
alerts may be presented via one or more of the tactile indicators. For
example, the tactile indicator 2924c may vibrate if an out-of-tolerance
condition is detected that would be adverse to dispensing of a marking
material, and therefore adverse to operation of the actuator 2916.

[0552]According to one embodiment, the nature of operation of each of the
tactile indicators in FIG. 30, in terms of what triggers vibration of the
tactile indicator, the type of vibration (intensity, duration, frequency,
pattern, etc.), and the meaning may be controlled by the control
electronics 2912. For example, the nature of operation of each of the
tactile indicators may be programmed into a processor of the control
electronics (e.g., similar to processor 118, previously described).

[0553]In one example, the tactile sensations programmed for tactile
indicator 2924a may be associated with the general operation of marking
device 2900 and/or aspects of the marking operations. In other words,
conditions associated with the general operation of marking device 2900
and/or aspects of the marking operations are communicated to the user via
tactile sensations at handle 2914. In this example, tactile sensations
provided at handle 2914 may be used to indicate any events that may occur
on and/or any conditions of the marking device. Examples of tactile
sensations that are provided at handle 2914 by tactile indicator 2924a
may include, but are not limited to, the following: [0554]1. when
powering on the marking device, a certain tactile sensation may indicate
the start of the boot cycle, followed by a "ready" tactile sensation;
[0555]2. a certain tactile sensation may indicate the status of certain
calibration processes and/or testing processes of components of the
marking device. This status may be indicated during or just following the
boot cycle. Additionally, this status may be indicated at any time during
the operation of the marking device that any component falls out of
calibration; [0556]3. a certain tactile sensation may indicate that
marking dispenser is installed and has been read successfully; [0557]4. a
certain tactile sensation may indicate a change in connectivity of the
marking device to a network (e.g., dropped or gained WiFi connectivity);
[0558]5. a certain tactile sensation may indicate a change in GPS
connectivity (e.g., dropped or gained); [0559]6. certain tactile
sensations may indicate that the battery power (e.g., power supply 114)
is below certain capacities (e.g., 75%, 50%, 25% capacity); [0560]7. a
certain tactile sensation may indicate that the marking device is not
oriented correctly (e.g., at the wrong angle); and [0561]8. any
combinations thereof.

[0562]In one embodiment, the tactile sensations programmed for tactile
indicator 2924b at the joystick 2920 may be associated with user
interface functions. In other words, when the user is using the joystick
or buttons to navigate through menus on display 2918, tactile feedback to
the user at the joystick 2920 may be used to communicate, for example, a
validation of certain selections or user interface functions. Examples of
tactile sensations that may be provided at joystick 2920 via tactile
indicator 2924b may include, but are not limited to, the following:
[0563]1. a certain tactile sensation may be provided when moving from
option to option of a menu of the display 2918; [0564]2. certain tactile
sensations may indicate the selection of different options of a menu of
the display 2918. For example: [0565]a. a certain tactile sensation may
indicate a job started selection and/or job stopped selection; [0566]b. a
certain tactile sensation may indicate that landmark mode was selected as
well as a certain type of landmark selected; [0567]c. a certain tactile
sensation may indicate that Bluetooth® communication is enabled
and/or disabled; [0568]d. a certain tactile sensation may indicate that
an invalid option has been selected. For example, the user has selected a
gas landmark, but no gas facility is indicated on the current locate
operation work order; or that the user has selected a gas landmark, but
the marking material color installed in the marking device does not
correspond to gas; and [0569]3. any combinations thereof.

[0570]In one embodiment, the tactile sensations programmed for tactile
indicator 2924c at actuator 2916 may be associated with the process of
dispensing marking material. In other words, conditions associated with
dispensing marking material from a marking dispenser may be communicated
to the user via tactile sensations at actuator 2916. Examples of tactile
sensations that may be provided at actuator 2916 via tactile indicator
2924c may include, but are not limited to, the following: [0571]1. when
the user presses actuator 2916, a certain tactile sensation may indicate
that no marking material is installed in the marking device; [0572]2.
when the user presses actuator 2916, a certain tactile sensation may
indicate that the wrong color marking material is installed in the
marking device. For example, blue marking material is installed, but no
water facility is indicated on the current locate operation work order;
[0573]3. when the user presses actuator 2916, a certain tactile sensation
may indicate an out of (or low) marking material condition; [0574]4. a
certain tactile sensation at actuator 2916 may be used to prompt the user
to activate actuator 2916 to dispense marking material; and [0575]5. any
combinations thereof.

[0576]Tactile sensations may also be generated based on information
received from one or more sources external to the marking device, such
as, but not limited to, external systems, external networks, external
computing devices, external business applications, and external
instrumentation, among others. For example, the marking device (e.g.,
marking device 2900) may be in communication with one or more external
devices, such as remote computer 150, via a network. The network may be,
for example, a local area network (LAN) and/or a wide area network (WAN).
The control electronics 2912 may be programmed to generate tactile
sensations via one or more of tactile indicators 2924a-2924c based on
information received from the remote computer 150.

[0577]Thus, further examples of scenarios which may trigger generation of
a tactile sensation via any one or more of the tactile indicators
2924a-2924c may include, but are not limited to, the following:
[0578]1. the marking device may receive workflow information and/or a
checklist with respect to performing locate operations according, for
example, to U.S. patent application Ser. No. 12/703,809, entitled
"Marking Apparatus Equipped with Ticket Processing Software for
Facilitating Marking Operations, and Associated Methods," filed Feb. 11,
2010, which application is hereby incorporated by reference. A certain
tactile sensation may be generated to indicate compliance and/or
non-compliance with the workflow and/or checklist; [0579]2. the marking
device may receive standard operating procedure (SOP) information with
respect to performing locate operations according to, for example, the
Best Practices Version 6.0 document, published in February 2009 by the
Common Ground Alliance (CGA) of Alexandria, Va.
(www.commongroundalliance.com) and/or the Recommended Marking Guidelines
For Underground Utilities as endorsed by the National Utility Locating
Contractors Association (NULCA) of North Kansas City, Mo. A certain
tactile sensation may be generated to indicate compliance and/or
non-compliance with the SOP information; [0580]3. the marking device may
receive wage and hour information with respect to performing locate
operations according to, for example, the wage and hour guidelines of one
or more regulatory bodies, such as federal, regional, state, and/or local
wage and hour guidelines. For example, a certain tactile sensation may be
generated to indicate compliance and/or non-compliance with the wage and
hour guidelines. Also, a certain tactile sensation may be generated to
indicate, for example, that it is time for a required break, it is time
for lunch, it is the end of the day, the employee is now in overtime mode
for the week, etc.; [0581]4. the marking device may receive quality
assessment information with respect to performing locate operations
according to, for example, a quality assessment application of the locate
company. A certain tactile sensation may be generated to indicate that
the locate operation has passed and/or failed the locate company's
quality assessment process; [0582]5. the marking device may receive VWL
information with respect to the current locate operation work order
according to, for example, the VWL application that is described with in
U.S. Patent Application Publication No. 20090238417, entitled "Virtual
white lines for indicating planned excavation sites on electronic
images;" that is incorporated by reference herein in its entirety. A
certain tactile sensation may be generated to indicate that the locate
operation is being performed inside and/or outside of the boundaries of
the associated VWL; [0583]6. the marking device may receive facilities
maps information with respect to the current locate operation work order.
A certain tactile sensation may be generated to indicate that the locate
operation is approaching the location of a certain facility that is
indicated on the facilities maps associated with the current locate
operation work order. Also, a tactile sensation may be generated to
indicate that certain types of facilities being located do not match the
types of facilities indicated on the facilities maps; [0584]7. the
marking device may receive information about prior locate operations
(e.g., historical work order information) with respect to the location of
the current locate operation. A certain tactile sensation may be
generated to indicate that the locate operation is approaching the
location of a certain facility that is indicated in the historical
information that is associated with the current locate operation work
order. Also, a tactile sensation may be generated to indicate that
certain types of facilities being located do not match the types of
facilities indicated by the historical locate information.

[0585]It should be appreciated that information about the generation of a
tactile signal may be included in an electronic record, a message, or any
other source of information including the other marking information
described herein. For example, information about whether a tactile signal
was generated, which tactile indicator generated the signal, the type of
signal (e.g., duration, frequency, intensity, etc.), the cause of the
signal, the time of the signal (e.g., from a timestamp), and/or the
geo-location at which the signal was issued, may be recorded, among other
things.

[0586]Table 22 illustrates an example of an event entry that may be made
in response to actuation of an actuation system of a marking device, in
which the marking device includes a tactile indicator. The illustrated
event entry is similar to that of Table 15, shown and described
previously, with the addition of an indication of whether a tactile
signal was generated (e.g., a "yes" or "no" indication being represented
by "Y" and "N" for "TCTL"). As in Table 15, for purposes of this event
format, the actuator is deemed to have three possible states, i.e.,
PRESSED, HELD and RELEASED. Marking information from one or more input
devices/other components of the marking device is recorded with these
events to provide information about the job in progress.

[0587]Table 23 illustrates an example of a data record that may be
generated by a marking device including a tactile indicator, as well as
various environmental and operational sensors. As shown, the data record
may include a "yes/no" indication of whether a tactile signal was
generated, as well as information about the type of signal. It should be
appreciated that other forms for the data are possible and that other
information regarding the tactile indicator may be included, such as any
of the types of information described above.

[0588]In those embodiments in which a marking device includes both a
tactile indicator and at least one accelerometer, data from the
accelerometer(s) may be used to verify whether a tactile indication was
generated, as the accelerometer data may reflect any physical movement of
the marking device, including the physical vibrations caused by a tactile
indicator. Thus, referring again to Table 23, for example, the
acceleration data may provide verification that the indicated tactile
signal was in fact generated.

[0589]It should be appreciated that many of the aspects of the present
invention described above also apply to a combination locate and marking
device. As explained, a locate receiver is a device typically used to
locate an underground facility, after which the location may be marked
using a marking device of the types described herein. According to one
embodiment, a single device may perform the function of a locate receiver
and a marking device, and thus may be a combination locate and marking
device, as described in U.S. patent application Ser. No. 12/569,192,
filed on Sep. 29, 2009 under Attorney Docket No. D0687.70010US01 and
titled "Methods, Apparatus, and Systems For Generating Electronic Records
Of Locate And Marking Operations, And Combined Locate And Marking
Apparatus For Same," which is hereby incorporated herein by reference in
its entirety. The various aspects described herein relating to marking
devices may also apply to such combination locate and marking devices as
those described in U.S. patent application Ser. No. 12/569,192.

XII. CONCLUSION

[0590]As discussed herein, a wide variety of information/data may be
acquired and analyzed in connection with marking operations, for a
variety of purposes. The data of interest that may be acquired and
analyzed may include, but is not limited to, t1 timestamp data, t2
timestamp data, geo-location information of physical locate marks,
geo-location information of environmental landmarks, direction
information, any information included in the standard data stream of the
locate tracking system (e.g., GPS system), color/type of marking
material, amount of marking material in marking dispenser, serial number
of marking dispenser (e.g., barcode, RFID), ID information (e.g.,
individual, vehicle, wage and/or hour compliance), battery status of the
marking device, angle of spray of marking material (e.g., using an
inclinometer), wired/wireless connection status, Bluetooth® signal
strength, storage capacity of the local memory, temperature, humidity,
light level, movement of the marking device, mode of operation of the
marking device, docking state of the marking device (e.g.,
docked/undocked, charging/not charging), alerts against expectations in
performance (e.g., compare amount and/or type of marking material sprayed
against facility maps), and any combination thereof.

[0591]The information, such as shown in various tables herein, that may be
acquired by use of the data acquisition system and methods described
herein, may be used for any purpose. In an embodiment, the information of
the data acquisition system may be analyzed against expected marking
operations in order to gain benefits in, for example, operating
efficiency, personnel management, inventory management, quality control,
training operations, safety, customer satisfaction, and the like.

[0592]Additionally, the information that is acquired by use of the data
acquisition system and the methods of the present disclosure may be
correlated to other aspects of locate and marking operations. For
example, the marking device data streams (e.g., respective event entries
or one or more electronic records transmitted by the marking device) may
be correlated to other data streams of multiple marking devices or any
other devices in order to aggregate, assess, evaluate, draw insights
from, take action on this information, and any combination thereof.
Correlating disparate data streams may be useful in order to better
interpret and/or gain new interpretations that are useful. For example,
by analyzing the aggregated data, field service providers may gain
visibility into the distributed workforce, may take corrective and/or any
other constructive action to improve process management, may improve
and/or develop best practices, and any combination thereof. In an
embodiment, certain trends may be identified by correlating historical
records of the amount of time that is spent performing locate and marking
operations to other information, such as, but not limited to, the time of
day, time of year, address of the locate site, experience of the locate
technician, weather conditions, heavy or light traffic times, and the
like.

[0593]While various inventive embodiments have been described and
illustrated herein, those of ordinary skill in the art will readily
envision a variety of other means and/or structures for performing the
function and/or obtaining the results and/or one or more of the
advantages described herein, and each of such variations and/or
modifications is deemed to be within the scope of the inventive
embodiments described herein. More generally, those skilled in the art
will readily appreciate that all parameters, dimensions, materials, and
configurations described herein are meant to be exemplary and that the
actual parameters, dimensions, materials, and/or configurations will
depend upon the specific application or applications for which the
inventive teachings is/are used. Those skilled in the art will recognize,
or be able to ascertain using no more than routine experimentation, many
equivalents to the specific inventive embodiments described herein. It
is, therefore, to be understood that the foregoing embodiments are
presented by way of example only and that, within the scope of the
appended claims and equivalents thereto, inventive embodiments may be
practiced otherwise than as specifically described and claimed. Inventive
embodiments of the present disclosure are directed to each individual
feature, system, article, material, kit, and/or method described herein.
In addition, any combination of two or more such features, systems,
articles, materials, kits, and/or methods, if such features, systems,
articles, materials, kits, and/or methods are not mutually inconsistent,
is included within the inventive scope of the present disclosure.

[0594]The above-described embodiments can be implemented in any of
numerous ways. For example, the embodiments may be implemented using
hardware, software or a combination thereof. When implemented in
software, the software code can be executed on any suitable processor or
collection of processors, whether provided in a single computer or
distributed among multiple computers.

[0595]The various methods or processes outlined herein may be coded as
software that is executable on one or more processors that employ any one
of a variety of operating systems or platforms. Additionally, such
software may be written using any of a number of suitable programming
languages and/or programming or scripting tools, and also may be compiled
as executable machine language code or intermediate code that is executed
on a framework or virtual machine.

[0596]In this respect, various inventive concepts may be embodied as a
computer readable storage medium (or multiple computer readable storage
media) (e.g., a computer memory, one or more floppy discs, compact discs,
optical discs, magnetic tapes, flash memories, circuit configurations in
Field Programmable Gate Arrays or other semiconductor devices, or other
non-transitory or tangible computer storage medium) encoded with one or
more programs that, when executed on one or more computers or other
processors, perform methods that implement the various embodiments of the
invention discussed above. The computer readable medium or media can be
transportable, such that the program or programs stored thereon can be
loaded onto one or more different computers or other processors to
implement various aspects of the present invention as discussed above.

[0597]The terms "program" or "software" are used herein in a generic sense
to refer to any type of computer code or set of computer-executable
instructions that can be employed to program a computer or other
processor to implement various aspects of embodiments as discussed above.
Additionally, it should be appreciated that according to one aspect, one
or more computer programs that when executed perform methods of the
present invention need not reside on a single computer or processor, but
may be distributed in a modular fashion amongst a number of different
computers or processors to implement various aspects of the present
invention.

[0598]Computer-executable instructions may be in many forms, such as
program modules, executed by one or more computers or other devices.
Generally, program modules include routines, programs, objects,
components, data structures, etc. that perform particular tasks or
implement particular abstract data types. Typically the functionality of
the program modules may be combined or distributed as desired in various
embodiments.

[0599]Also, data structures may be stored in computer-readable media in
any suitable form. For simplicity of illustration, data structures may be
shown to have fields that are related through location in the data
structure. Such relationships may likewise be achieved by assigning
storage for the fields with locations in a computer-readable medium that
conveys relationship between the fields. However, any suitable mechanism
may be used to establish a relationship between information in fields of
a data structure, including through the use of pointers, tags or other
mechanisms that establish relationship between data elements.

[0600]Also, various inventive concepts may be embodied as one or more
methods, of which an example has been provided. The acts performed as
part of the method may be ordered in any suitable way. Accordingly,
embodiments may be constructed in which acts are performed in an order
different than illustrated, which may include performing some acts
simultaneously, even though shown as sequential acts in illustrative
embodiments.

[0601]All definitions, as defined and used herein, should be understood to
control over dictionary definitions, definitions in documents
incorporated by reference, and/or ordinary meanings of the defined terms.

[0602]The indefinite articles "a" and "an," as used herein in the
specification and in the claims, unless clearly indicated to the
contrary, should be understood to mean "at least one."

[0603]The phrase "and/or," as used herein in the specification and in the
claims, should be understood to mean "either or both" of the elements so
conjoined, i.e., elements that are conjunctively present in some cases
and disjunctively present in other cases. Multiple elements listed with
"and/or" should be construed in the same fashion, i.e., "one or more" of
the elements so conjoined. Other elements may optionally be present other
than the elements specifically identified by the "and/or" clause, whether
related or unrelated to those elements specifically identified. Thus, as
a non-limiting example, a reference to "A and/or B", when used in
conjunction with open-ended language such as "comprising" can refer, in
one embodiment, to A only (optionally including elements other than B);
in another embodiment, to B only (optionally including elements other
than A); in yet another embodiment, to both A and B (optionally including
other elements); etc.

[0604]As used herein in the specification and in the claims, "or" should
be understood to have the same meaning as "and/or" as defined above. For
example, when separating items in a list, "or" or "and/or" shall be
interpreted as being inclusive, i.e., the inclusion of at least one, but
also including more than one, of a number or list of elements, and,
optionally, additional unlisted items. Only terms clearly indicated to
the contrary, such as "only one of" or "exactly one of," or, when used in
the claims, "consisting of," will refer to the inclusion of exactly one
element of a number or list of elements. In general, the term "or" as
used herein shall only be interpreted as indicating exclusive
alternatives (i.e. "one or the other but not both") when preceded by
terms of exclusivity, such as "either," "one of," "only one of," or
"exactly one of." "Consisting essentially of," when used in the claims,
shall have its ordinary meaning as used in the field of patent law.

[0605]As used herein in the specification and in the claims, the phrase
"at least one," in reference to a list of one or more elements, should be
understood to mean at least one element selected from any one or more of
the elements in the list of elements, but not necessarily including at
least one of each and every element specifically listed within the list
of elements and not excluding any combinations of elements in the list of
elements. This definition also allows that elements may optionally be
present other than the elements specifically identified within the list
of elements to which the phrase "at least one" refers, whether related or
unrelated to those elements specifically identified. Thus, as a
non-limiting example, "at least one of A and B" (or, equivalently, "at
least one of A or B," or, equivalently "at least one of A and/or B") can
refer, in one embodiment, to at least one, optionally including more than
one, A, with no B present (and optionally including elements other than
B); in another embodiment, to at least one, optionally including more
than one, B, with no A present (and optionally including elements other
than A); in yet another embodiment, to at least one, optionally including
more than one, A, and at least one, optionally including more than one, B
(and optionally including other elements); etc.

[0606]In the claims, as well as in the specification above, all
transitional phrases such as "comprising," "including," "carrying,"
"having," "containing," "involving," "holding," "composed of," and the
like are to be understood to be open-ended, i.e., to mean including but
not limited to. Only the transitional phrases "consisting of" and
"consisting essentially of" shall be closed or semi-closed transitional
phrases, respectively, as set forth in the United States Patent Office
Manual of Patent Examining Procedures, Section 2111.03.